| Saturday, January 28 |
| Former Cub Ray Harrell dies in Alexandria, LA at the age of 72. |
| Monday, April 2 |
| » Major-league debuts: Ross Jones (Mets) |
| Tuesday, April 3 |
| » Defeated Giants (0-1), 5-3 | Candlestick Park (1-0) | 1-0 | |
| » W: Dick Ruthven (1-0) L: Mark Davis (0-1) S: Lee Smith (1) | First | -- |
| Thursday, April 5 |
| » Defeated Giants (0-2), 11-7 | Candlestick Park (2-0) | 2-0 | Won 2 |
| » W: Chuck Rainey (1-0) L: Mike Krukow (0-1) S: Lee Smith (2) | First | -- |
| » Major-league debuts: Frank Williams (Giants) Henry Cotto (Cubs) |
| Friday, April 6 |
| » Lost to Padres (3-0), 3-2 | San Diego/Jack Murphy Stadium (0-1) | 2-1 | |
| » W: Sid Monge (1-0) L: Lee Smith (0-1) | First | -- |
| Saturday, April 7 |
| » Lost to Padres (4-0), 7-6 | San Diego/Jack Murphy Stadium (0-2) | 2-2 | Lost 2 |
| » W: Dave Dravecky (1-0) L: Steve Trout (0-1) S: Rich Gossage (2) | Second | 1 out |
| Sunday, April 8 |
| » Defeated Padres (4-1), 8-5 | San Diego/Jack Murphy Stadium (1-2) | 3-2 | |
| » W: Lee Smith (1-1) L: Mark Thurmond (0-1) | Second | 1 out |
| Monday, April 9 |
| » Lost to Dodgers (2-4), 4-2 | Dodger Stadium (0-1) | 3-3 | |
| » W: Jerry Reuss (1-0) L: Chuck Rainey (1-1) S: Tom Niedenfuer (1) | Third | 1½ out |
| Wednesday, April 11 |
| » Lost to Dodgers (3-4), 2-1 | Dodger Stadium (0-2) | 3-4 | Lost 2 |
| » W: Rick Honeycutt (1-0) L: Scott Sanderson (0-1) | Fourth | 3 out |
| Friday, April 13 |
| » Defeated Mets (6-2), 11-2 | Wrigley Field (1-0) | 4-4 | |
| » W: Steve Trout (1-1) L: Dwight Gooden (1-1) | Fourth | 2 out |
| Saturday, April 14 |
| » Defeated Mets (6-3), 5-2 | Wrigley Field (2-0) | 5-4 | Won 2 |
| » W: Dick Ruthven (2-0) L: Tim Leary (1-1) S: Lee Smith (3) | Second | 1 out |
| Wednesday, April 18 |
| » Lost to Cardinals (7-4), 5-0 | Wrigley Field (2-1) | 5-5 | |
| » W: Joaquin Andujar (2-1) L: Chuck Rainey (1-2) | Third | 1 out |
| » Defeated Cardinals (7-5), 6-1 | Wrigley Field (3-1) | 6-5 | |
| » W: Scott Sanderson (1-1) L: Dave LaPoint (1-2) | Third | 1 out |
| Thursday, April 19 |
| » Defeated Cardinals (7-6), 6-1 | Wrigley Field (4-1) | 7-5 | Won 2 |
| » W: Steve Trout (2-1) L: Danny Cox (2-1) | Third | 1 out |
| Friday, April 20 |
| » Defeated Pirates (4-9), 5-4 | Wrigley Field (5-1) | 8-5 | Won 3 |
| » W: Tim Stoddard (1-0) L: Kent Tekulve (0-1) | Second | 1 out |
| Saturday, April 21 |
| » Lost to Pirates (5-9), 8-5 | Wrigley Field (5-2) | 8-6 | |
| » W: Jose DeLeon (1-0) L: Dickie Noles (0-1) S: Don Robinson (3) | Third | 1 out |
| Monday, April 23 |
| » Defeated Cardinals (7-10), 6-2 | Busch Stadium II (1-0) | 9-6 | |
| » W: Scott Sanderson (2-1) L: Dave LaPoint (1-3) | Second | ½ out |
| Tuesday, April 24 |
| » Defeated Cardinals (7-11), 3-2 | Busch Stadium II (2-0) | 10-6 | Won 2 |
| » W: Tim Stoddard (2-0) L: Bruce Sutter (0-1) S: Lee Smith (4) | First | -- |
| Wednesday, April 25 |
| » Lost to Cardinals (8-11), 7-5 | Busch Stadium II (2-1) | 10-7 | |
| » W: Jeff Lahti (1-1) L: Dick Ruthven (2-1) S: Bruce Sutter (5) | Second | ½ out |
| Friday, April 27 |
| » Lost to Pirates (7-10), 3-2 | Three Rivers Stadium (0-1) | 10-8 | Lost 2 |
| » W: Rick Rhoden (2-2) L: Chuck Rainey (1-3) S: Kent Tekulve (2) | Second | 1½ out |
| Saturday, April 28 |
| » Defeated Pirates (7-11), 7-1 | Three Rivers Stadium (1-1) | 11-8 | |
| » W: Scott Sanderson (3-1) L: Larry McWilliams (0-3) | Second | ½ out |
| Sunday, April 29 |
| » Defeated Pirates (7-12), 2-1 | Three Rivers Stadium (2-1) | 12-8 | Won 2 |
| » W: Steve Trout (3-1) L: John Candelaria (3-2) S: Lee Smith (5) | First | -- |
| Tuesday, May 1 |
| » Lost to Mets (13-8), 8-1 | Shea Stadium (0-1) | 12-9 | |
| » W: Dwight Gooden (2-1) L: Dick Ruthven (2-2) | Second | 1 out |
| Wednesday, May 2 |
| » Lost to Mets (14-8), 4-3 | Shea Stadium (0-2) | 12-10 | Lost 2 |
| » W: Ed Lynch (3-0) L: Lee Smith (1-2) | Second | 2 out |
| Friday, May 4 |
| » Defeated Padres (16-10), 7-6 | Wrigley Field (6-2) | 13-10 | |
| » W: Lee Smith (2-2) L: Sid Monge (2-1) | Second | 2 out |
| Saturday, May 5 |
| » Defeated Padres (16-11), 6-5 | Wrigley Field (7-2) | 14-10 | Won 2 |
| » W: Warren Brusstar (1-0) L: Craig Lefferts (0-1) | Second | 1 out |
| Sunday, May 6 |
| » Lost to Padres (17-11), 8-5 | Wrigley Field (7-3) | 14-11 | |
| » W: Eric Show (5-1) L: Dick Ruthven (2-3) | Second | 1 out |
| Monday, May 7 |
| » Defeated Giants (11-18), 10-7 | Wrigley Field (8-3) | 15-11 | |
| » W: Chuck Rainey (2-3) L: Mark Davis (0-4) S: Tim Stoddard (1) | First | -- |
| Tuesday, May 8 |
| » Defeated Giants (11-19), 12-11 | Wrigley Field (9-3) | 16-11 | Won 2 |
| » W: Lee Smith (3-2) L: Greg Minton (1-2) | First | -- |
| Wednesday, May 9 |
| » Defeated Dodgers (20-13), 7-0 | Wrigley Field (10-3) | 17-11 | Won 3 |
| » W: Scott Sanderson (4-1) L: Burt Hooton (0-1) S: Rich Bordi (1) | First | -- |
| Thursday, May 10 |
| » Lost to Dodgers (21-13), 5-1 | Wrigley Field (10-4) | 17-12 | |
| » W: Bob Welch (3-3) L: Steve Trout (3-2) | First | -- |
| Friday, May 11 |
| » Lost to Astros (13-18), 3-1 | Astrodome (0-1) | 17-13 | Lost 2 |
| » W: Nolan Ryan (3-2) L: Dick Ruthven (2-4) S: Frank DiPino (5) | Second | ½ out |
| Saturday, May 12 |
| » Defeated Astros (13-19), 5-4 | Astrodome (1-1) | 18-13 | |
| » W: Dickie Noles (1-1) L: Frank DiPino (1-2) S: Lee Smith (6) | Second | ½ out |
| Sunday, May 13 |
| » Lost to Astros (14-19), 1-0 | Astrodome (1-2) | 18-14 | |
| » W: Mike Madden (1-1) L: Rick Reuschel (0-1) S: Vern Ruhle (2) | Second | ½ out |
| Tuesday, May 15 |
| » Defeated Reds (19-16), 6-3 | Riverfront Stadium (1-0) | 19-14 | |
| » W: Dickie Noles (2-1) L: Frank Pastore (2-3) S: Tim Stoddard (2) | Second | ½ out |
| Wednesday, May 16 |
| » Defeated Reds (19-17), 10-4 | Riverfront Stadium (2-0) | 20-14 | Won 2 |
| » W: Steve Trout (4-2) L: Jeff Russell (2-4) | First | -- |
| Thursday, May 17 |
| » Lost to Reds (20-17), 5-3 | Riverfront Stadium (2-1) | 20-15 | |
| » W: Mario Soto (6-1) L: Dick Ruthven (2-5) | Second | 1 out |
| Friday, May 18 |
| » Defeated Astros (15-22), 7-6 | Wrigley Field (11-4) | 21-15 | |
| » W: Tim Stoddard (3-0) L: Dave Smith (0-1) | First | -- |
| Saturday, May 19 |
| » Defeated Astros (15-23), 5-4 | Wrigley Field (12-4) | 22-15 | Won 2 |
| » W: Rick Reuschel (1-1) L: Bill Dawley (2-3) S: Lee Smith (7) | First | -- |
| Sunday, May 20 |
| » Defeated Astros (15-24), 10-3 | Wrigley Field (13-4) | 23-15 | Won 3 |
| » W: Rich Bordi (1-0) L: Mike Scott (2-2) | First | -- |
| Wednesday, May 23 |
| » Defeated Braves (21-19), 3-1 | Wrigley Field (14-4) | 24-15 | Won 4 |
| » W: Steve Trout (5-2) L: Craig McMurtry (3-5) S: Lee Smith (8) | First | -- |
| Thursday, May 24 |
| » Defeated Braves (21-20), 10-7 | Wrigley Field (15-4) | 25-15 | Won 5 |
| » W: Chuck Rainey (3-3) L: Pascual Perez (3-1) S: Warren Brusstar (1) | First | -- |
| » Defeated Braves (21-21), 7-5 | Wrigley Field (16-4) | 26-15 | Won 6 |
| » W: Rick Reuschel (2-1) L: Pete Falcone (2-5) S: Rich Bordi (2) | First | -- |
| Friday, May 25 |
| » Lost to Reds (22-22), 3-0 | Wrigley Field (16-5) | 26-16 | |
| » W: Tom Hume (3-4) L: Dickie Noles (2-2) S: Ted Power (1) | First | -- |
| Saturday, May 26 |
| » Lost to Reds (23-22), 7-6 | Wrigley Field (16-6) | 26-17 | Lost 2 |
| » W: Bill Scherrer (1-0) L: Steve Trout (5-3) S: Ted Power (2) | First | -- |
| Sunday, May 27 |
| » Lost to Reds (24-22), 4-3 | Wrigley Field (16-7) | 26-18 | Lost 3 |
| » W: Bruce Berenyi (2-5) L: Dennis Eckersley (4-5) | First | -- |
| Tuesday, May 29 |
| » Lost to Braves (25-22), 7-4 | Atlanta-Fulton County Stadium (0-1) | 26-19 | Lost 4 |
| » W: Pascual Perez (4-1) L: Warren Brusstar (1-1) S: Terry Forster (3) | First | -- |
| Wednesday, May 30 |
| » Defeated Braves (25-23), 6-2 | Atlanta-Fulton County Stadium (1-1) | 27-19 | |
| » W: Steve Trout (6-3) L: Len Barker (4-5) S: Lee Smith (9) | First | -- |
| Thursday, May 31 |
| » Lost to Phillies (27-19), 10-2 | Veteran's Stadium (0-1) | 27-20 | |
| » W: Charles Hudson (6-3) L: Chuck Rainey (3-4) | Second | ½ out |
| Friday, June 1 |
| » Defeated Phillies (27-20), 12-3 | Veteran's Stadium (1-1) | 28-20 | |
| » W: Rick Reuschel (3-1) L: Marty Bystrom (2-2) | First | -- |
| Saturday, June 2 |
| » Lost to Phillies (28-20), 3-2 | Veteran's Stadium (1-2) | 28-21 | |
| » W: Al Holland (4-2) L: Lee Smith (3-3) | Second | ½ out |
| Sunday, June 3 |
| » Defeated Phillies (28-21), 11-2 | Veteran's Stadium (2-2) | 29-21 | |
| » W: Steve Trout (7-3) L: Kevin Gross (1-1) S: Warren Brusstar (2) | First | -- |
| Tuesday, June 5 |
| » Defeated Expos (25-27), 3-2 | Stade Olympique (1-0) | 30-21 | Won 2 |
| » W: Chuck Rainey (4-4) L: Bryn Smith (5-5) S: Lee Smith (10) | First | -- |
| Wednesday, June 6 |
| » Lost to Expos (26-27), 8-1 | Stade Olympique (1-1) | 30-22 | |
| » W: Bill Gullickson (2-5) L: Rick Reuschel (3-2) | First | -- |
| Thursday, June 7 |
| » Lost to Expos (27-27), 2-1 | Stade Olympique (1-2) | 30-23 | Lost 2 |
| » W: Charlie Lea (10-2) L: Dennis Eckersley (4-6) | First | -- |
| Friday, June 8 |
| » Lost to Cardinals (30-28), 5-4 | Busch Stadium II (2-2) | 30-24 | Lost 3 |
| » W: Jeff Lahti (2-1) L: Tim Stoddard (3-1) S: Bruce Sutter (14) | First | -- |
| Saturday, June 9 |
| » Defeated Cardinals (30-29), 5-0 | Busch Stadium II (3-2) | 31-24 | |
| » W: Rich Bordi (2-0) L: John Stuper (2-3) | First | -- |
| Sunday, June 10 |
| » Defeated Cardinals (30-30), 2-0 | Busch Stadium II (4-2) | 32-24 | Won 2 |
| » W: Chuck Rainey (5-4) L: Joaquin Andujar (10-5) S: Lee Smith (11) | First | -- |
| Monday, June 11 |
| » Lost to Expos (29-30), 2-1 | Wrigley Field (16-8) | 32-25 | |
| » W: Bob James (2-3) L: Lee Smith (3-4) | First | -- |
| Tuesday, June 12 |
| » Defeated Expos (29-31), 11-4 | Wrigley Field (17-8) | 33-25 | |
| » W: Dennis Eckersley (5-6) L: Charlie Lea (10-3) | First | -- |
| Wednesday, June 13 |
| » Defeated Expos (29-32), 7-4 | Wrigley Field (18-8) | 34-25 | Won 2 |
| » W: Tim Stoddard (4-1) L: Gary Lucas (0-1) S: Lee Smith (12) | First | -- |
| Thursday, June 14 |
| » Lost to Phillies (33-27), 11-2 | Wrigley Field (18-9) | 34-26 | |
| » W: Steve Carlton (4-3) L: Rich Bordi (2-1) | First | -- |
| Friday, June 15 |
| » Lost to Phillies (34-27), 5-2 | Wrigley Field (18-10) | 34-27 | Lost 2 |
| » W: Charles Hudson (7-4) L: Chuck Rainey (5-5) S: Al Holland (14) | Second | 1½ out |
| Saturday, June 16 |
| » Lost to Phillies (35-27), 8-2 | Wrigley Field (18-11) | 34-28 | Lost 3 |
| » W: Marty Bystrom (3-3) L: Rick Reuschel (3-3) | Third | 1½ out |
| Sunday, June 17 |
| » Lost to Phillies (36-27), 9-7 | Wrigley Field (18-12) | 34-29 | Lost 4 |
| » W: Kevin Gross (3-2) L: Dennis Eckersley (5-7) S: Al Holland (15) | Third | 2 out |
| Former Cub Jim Hegan dies in Swampscott, MA at the age of 64. |
| Tuesday, June 19 |
| » Defeated Pirates (24-39), 4-3 | Three Rivers Stadium (3-1) | 35-29 | |
| » W: Rick Sutcliffe (5-5) L: John Tudor (4-4) S: Lee Smith (13) | Third | 2 out |
| Wednesday, June 20 |
| » Lost to Pirates (25-39), 5-1 | Three Rivers Stadium (3-2) | 35-30 | |
| » W: Jose DeLeon (4-4) L: Chuck Rainey (5-6) | Third | 2 out |
| Thursday, June 21 |
| » Lost to Pirates (26-39), 8-6 | Three Rivers Stadium (3-3) | 35-31 | Lost 2 |
| » W: Rick Rhoden (5-5) L: Dennis Eckersley (5-8) S: Kent Tekulve (6) | Third | 2½ out |
| Friday, June 22 |
| » Defeated Cardinals (34-36), 9-3 | Wrigley Field (19-12) | 36-31 | |
| » W: Rick Reuschel (4-3) L: John Stuper (2-5) S: Lee Smith (14) | Third | 1½ out |
| Saturday, June 23 |
| » Defeated Cardinals (34-37), 12-11 | Wrigley Field (20-12) | 37-31 | Won 2 |
| » W: Lee Smith (4-4) L: Dave Rucker (1-1) | Third | 1½ out |
| Sunday, June 24 |
| » Defeated Cardinals (34-38), 5-0 | Wrigley Field (21-12) | 38-31 | Won 3 |
| » W: Rick Sutcliffe (6-5) L: Ricky Horton (3-1) | Third | 1½ out |
| Monday, June 25 |
| » Lost to Pirates (29-41), 3-0 | Wrigley Field (21-13) | 38-32 | |
| » W: Jose DeLeon (5-4) L: Chuck Rainey (5-7) | Third | 1½ out |
| Tuesday, June 26 |
| » Lost to Pirates (30-41), 9-0 | Wrigley Field (21-14) | 38-33 | Lost 2 |
| » W: Rick Rhoden (6-5) L: Dennis Eckersley (5-9) | Third | 2 out |
| » Defeated Pirates (30-42), 9-8 | Wrigley Field (22-14) | 39-33 | |
| » W: Rich Bordi (3-1) L: Larry McWilliams (4-6) S: Lee Smith (15) | Third | 2 out |
| Wednesday, June 27 |
| » Defeated Pirates (30-43), 8-7 | Wrigley Field (23-14) | 40-33 | Won 2 |
| » W: Tim Stoddard (5-1) L: Rod Scurry (1-4) | Third | 1 out |
| Thursday, June 28 |
| » Defeated Dodgers (40-38), 5-3 | Dodger Stadium (1-2) | 41-33 | Won 3 |
| » W: Steve Trout (8-3) L: Alejandro Pena (8-4) S: Tim Stoddard (3) | First | -- |
| Friday, June 29 |
| » Lost to Dodgers (41-38), 7-1 | Dodger Stadium (1-3) | 41-34 | |
| » W: Orel Hershiser (3-3) L: Rick Sutcliffe (6-6) | Second | 1 out |
| Saturday, June 30 |
| » Defeated Dodgers (41-39), 14-4 | Dodger Stadium (2-3) | 42-34 | |
| » W: George Frazier (4-2) L: Ken Howell (0-1) S: Tim Stoddard (4) | First | -- |
| Sunday, July 1 |
| » Defeated Dodgers (41-40), 4-3 | Dodger Stadium (3-3) | 43-34 | Won 2 |
| » W: Dennis Eckersley (6-9) L: Fernando Valenzuela (8-9) S: Warren Brusstar (3) | First | -- |
| Monday, July 2 |
| » Lost to Padres (46-31), 5-1 | San Diego/Jack Murphy Stadium (1-3) | 43-35 | |
| » W: Dave Dravecky (5-4) L: Rick Reuschel (4-4) | Second | 2 out |
| Tuesday, July 3 |
| » Defeated Padres (46-32), 3-2 | San Diego/Jack Murphy Stadium (2-3) | 44-35 | |
| » W: Steve Trout (9-3) L: Mark Thurmond (5-4) S: Tim Stoddard (5) | Second | 2 out |
| Wednesday, July 4 |
| » Defeated Padres (46-33), 2-1 | San Diego/Jack Murphy Stadium (3-3) | 45-35 | Won 2 |
| » W: Rick Sutcliffe (7-6) L: Eric Show (8-6) S: Lee Smith (16) | First | -- |
| Thursday, July 5 |
| » Defeated Giants (32-48), 9-3 | Candlestick Park (3-0) | 46-35 | Won 3 |
| » W: Scott Sanderson (5-1) L: Bill Laskey (4-8) S: Rich Bordi (3) | First | -- |
| Friday, July 6 |
| » Defeated Giants (32-49), 5-4 | Candlestick Park (4-0) | 47-35 | Won 4 |
| » W: Tim Stoddard (6-1) L: Greg Minton (1-6) S: Lee Smith (17) | First | -- |
| Saturday, July 7 |
| » Lost to Giants (33-49), 7-2 | Candlestick Park (4-1) | 47-36 | |
| » W: Mike Krukow (5-7) L: Rick Reuschel (4-5) | Second | 1½ out |
| Sunday, July 8 |
| » Defeated Giants (33-50), 6-3 | Candlestick Park (5-1) | 48-36 | |
| » W: Rick Sutcliffe (8-6) L: Mark Davis (3-8) S: Lee Smith (18) | Second | 1½ out |
| Thursday, July 12 |
| » Defeated Dodgers (45-44), 3-2 | Wrigley Field (24-14) | 49-36 | Won 2 |
| » W: Tim Stoddard (7-1) L: Tom Niedenfuer (1-5) | Second | 1½ out |
| Friday, July 13 |
| » Defeated Dodgers (45-45), 7-5 | Wrigley Field (25-14) | 50-36 | Won 3 |
| » W: Rick Sutcliffe (9-6) L: Bob Welch (6-10) S: Lee Smith (19) | Second | 1½ out |
| Saturday, July 14 |
| » Lost to Dodgers (46-45), 8-0 | Wrigley Field (25-15) | 50-37 | |
| » W: Orel Hershiser (5-3) L: Scott Sanderson (5-2) | Second | 1½ out |
| Sunday, July 15 |
| » Defeated Dodgers (46-46), 4-1 | Wrigley Field (26-15) | 51-37 | |
| » W: Dennis Eckersley (7-9) L: Fernando Valenzuela (8-10) S: Lee Smith (20) | Second | 1½ out |
| Monday, July 16 |
| » Lost to Padres (52-36), 4-0 | Wrigley Field (26-16) | 51-38 | |
| » W: Mark Thurmond (6-5) L: Dick Ruthven (2-6) | Second | 1½ out |
| Tuesday, July 17 |
| » Lost to Padres (53-36), 6-5 | Wrigley Field (26-17) | 51-39 | Lost 2 |
| » W: Eric Show (10-6) L: Steve Trout (9-4) S: Rich Gossage (16) | Second | 1½ out |
| Wednesday, July 18 |
| » Defeated Padres (53-37), 4-1 | Wrigley Field (27-17) | 52-39 | |
| » W: Rick Sutcliffe (10-6) L: Ed Whitson (10-5) | Second | 1½ out |
| Thursday, July 19 |
| » Defeated Giants (35-57), 6-4 | Wrigley Field (28-17) | 53-39 | Won 2 |
| » W: George Frazier (5-2) L: Mark Davis (3-10) S: Tim Stoddard (6) | Second | 1½ out |
| Friday, July 20 |
| » Lost to Giants (36-57), 3-2 | Wrigley Field (28-18) | 53-40 | |
| » W: Jeff Robinson (5-11) L: Dennis Eckersley (7-10) S: Greg Minton (10) | Second | 1½ out |
| Saturday, July 21 |
| » Defeated Giants (36-58), 4-3 | Wrigley Field (29-18) | 54-40 | |
| » W: Rich Bordi (4-1) L: Greg Minton (1-7) | Second | 1½ out |
| Sunday, July 22 |
| » Lost to Giants (37-58), 11-5 | Wrigley Field (29-19) | 54-41 | |
| » W: Mike Krukow (7-8) L: Steve Trout (9-5) | Second | 2½ out |
| Monday, July 23 |
| » Defeated Phillies (53-43), 3-2 | Veteran's Stadium (3-2) | 55-41 | |
| » W: Rick Sutcliffe (11-6) L: Shane Rawley (5-5) S: Lee Smith (21) | Second | 2½ out |
| Tuesday, July 24 |
| » Lost to Phillies (54-43), 3-2 | Veteran's Stadium (3-3) | 55-42 | |
| » W: Jerry Koosman (12-7) L: Tim Stoddard (7-2) S: Al Holland (22) | Second | 3½ out |
| Wednesday, July 25 |
| » Defeated Phillies (54-44), 9-4 | Veteran's Stadium (4-3) | 56-42 | |
| » W: Dennis Eckersley (8-10) L: Charles Hudson (8-8) | Second | 3½ out |
| Friday, July 27 |
| » Lost to Mets (59-37), 2-1 | Shea Stadium (0-3) | 56-43 | |
| » W: Dwight Gooden (9-6) L: Dick Ruthven (2-7) S: Jesse Orosco (21) | Second | 4½ out |
| Saturday, July 28 |
| » Defeated Mets (59-38), 11-4 | Shea Stadium (1-3) | 57-43 | |
| » W: Lee Smith (5-4) L: Doug Sisk (1-3) | Second | 3½ out |
| Sunday, July 29 |
| » Defeated Mets (59-39), 3-0 | Shea Stadium (2-3) | 58-43 | Won 2 |
| » W: Steve Trout (10-5) L: Walt Terrell (8-8) | Second | 1½ out |
| » Defeated Mets (59-40), 5-1 | Shea Stadium (3-3) | 59-43 | Won 3 |
| » W: Scott Sanderson (6-2) L: Bruce Berenyi (7-11) | Second | 1½ out |
| » Major-league debuts: Wes Gardner (Mets) |
| Monday, July 30 |
| » Defeated Phillies (55-47), 3-2 | Wrigley Field (30-19) | 60-43 | Won 4 |
| » W: Dennis Eckersley (9-10) L: Charles Hudson (8-9) S: Lee Smith (22) | Second | 1½ out |
| Tuesday, July 31 |
| » Lost to Phillies (56-47), 2-1 | Wrigley Field (30-20) | 60-44 | |
| » W: Al Holland (5-5) L: Tim Stoddard (7-3) S: Bill Campbell (1) | Second | 1½ out |
| Wednesday, August 1 |
| » Defeated Phillies (56-48), 5-4 | Wrigley Field (31-20) | 61-44 | |
| » W: Lee Smith (6-4) L: Al Holland (5-6) | First | -- |
| Thursday, August 2 |
| » Defeated Expos (51-54), 3-2 | Wrigley Field (32-20) | 62-44 | Won 2 |
| » W: Rick Sutcliffe (12-6) L: Bryn Smith (9-9) S: Lee Smith (23) | First | -- |
| Friday, August 3 |
| » Lost to Expos (52-54), 6-5 | Wrigley Field (32-21) | 62-45 | |
| » W: Jeff Reardon (4-4) L: Tim Stoddard (7-4) | First | -- |
| Saturday, August 4 |
| » Defeated Expos (52-55), 4-1 | Wrigley Field (33-21) | 63-45 | |
| » W: Dennis Eckersley (10-10) L: Dan Schatzeder (4-3) S: George Frazier (2) | First | -- |
| Sunday, August 5 |
| » Defeated Expos (52-56), 4-3 | Wrigley Field (34-21) | 64-45 | Won 2 |
| » W: Rick Reuschel (5-5) L: Rick Grapenthin (0-1) S: Lee Smith (24) | First | -- |
| Monday, August 6 |
| » Defeated Mets (62-45), 9-3 | Wrigley Field (35-21) | 65-45 | Won 3 |
| » W: Dick Ruthven (3-7) L: Dwight Gooden (9-8) | First | -- |
| Tuesday, August 7 |
| » Defeated Mets (62-46), 8-6 | Wrigley Field (36-21) | 66-45 | Won 4 |
| » W: Rick Sutcliffe (13-6) L: Ron Darling (10-5) S: George Frazier (3) | First | -- |
| » Defeated Mets (62-47), 8-4 | Wrigley Field (37-21) | 67-45 | Won 5 |
| » W: Tim Stoddard (8-4) L: Ed Lynch (8-7) S: Lee Smith (25) | First | -- |
| Wednesday, August 8 |
| » Defeated Mets (62-48), 7-6 | Wrigley Field (38-21) | 68-45 | Won 6 |
| » W: Lee Smith (7-4) L: Wes Gardner (1-1) S: Tim Stoddard (7) | First | -- |
| Thursday, August 9 |
| » Lost to Expos (55-58), 1-0 | Stade Olympique (1-3) | 68-46 | |
| » W: Dan Schatzeder (5-3) L: George Frazier (5-3) | First | -- |
| Friday, August 10 |
| » Lost to Expos (56-58), 4-2 | Stade Olympique (1-4) | 68-47 | Lost 2 |
| » W: Bob James (5-4) L: Tim Stoddard (8-5) | First | -- |
| Saturday, August 11 |
| » Defeated Expos (56-59), 2-1 | Stade Olympique (2-4) | 69-47 | |
| » W: Lee Smith (8-4) L: Charlie Lea (14-8) | First | -- |
| Sunday, August 12 |
| » Defeated Expos (56-60), 7-3 | Stade Olympique (3-4) | 70-47 | Won 2 |
| » W: Rick Sutcliffe (14-6) L: Steve Rogers (3-12) | First | -- |
| Monday, August 13 |
| » Lost to Astros (58-62), 2-1 | Astrodome (1-3) | 70-48 | |
| » W: Bill Dawley (7-4) L: Scott Sanderson (6-3) | First | -- |
| Tuesday, August 14 |
| » Lost to Astros (59-62), 7-6 | Astrodome (1-4) | 70-49 | Lost 2 |
| » W: Julio Solano (1-2) L: George Frazier (5-4) S: Frank DiPino (10) | First | -- |
| Former Cub Lynn McGlothen dies in Dubach, LA at the age of 35. |
| Wednesday, August 15 |
| » Lost to Astros (60-62), 6-2 | Astrodome (1-5) | 70-50 | Lost 3 |
| » W: Bob Knepper (12-8) L: Dennis Eckersley (10-11) S: Frank DiPino (11) | First | -- |
| Friday, August 17 |
| » Lost to Reds (52-70), 6-4 | Riverfront Stadium (2-2) | 70-51 | Lost 4 |
| » W: Mario Soto (13-6) L: Dick Ruthven (3-8) | First | -- |
| Saturday, August 18 |
| » Defeated Reds (52-71), 13-11 | Riverfront Stadium (3-2) | 71-51 | |
| » W: Rick Sutcliffe (15-6) L: Ron Robinson (0-1) S: Lee Smith (26) | First | -- |
| Sunday, August 19 |
| » Defeated Reds (52-72), 9-6 | Riverfront Stadium (4-2) | 72-51 | Won 2 |
| » W: George Frazier (6-4) L: Jeff Russell (5-14) | First | -- |
| Monday, August 20 |
| » Defeated Astros (63-63), 6-1 | Wrigley Field (39-21) | 73-51 | Won 3 |
| » W: Steve Trout (11-5) L: Bob Knepper (12-9) | First | -- |
| Tuesday, August 21 |
| » Defeated Astros (63-64), 11-5 | Wrigley Field (40-21) | 74-51 | Won 4 |
| » W: Dennis Eckersley (11-11) L: Mike Scott (5-11) | First | -- |
| Wednesday, August 22 |
| » Lost to Astros (64-64), 8-3 | Wrigley Field (40-22) | 74-52 | |
| » W: Nolan Ryan (11-7) L: Dick Ruthven (3-9) | First | -- |
| Friday, August 24 |
| » Defeated Braves (64-64), 3-0 | Wrigley Field (41-22) | 75-52 | |
| » W: Rick Sutcliffe (16-6) L: Rick Camp (6-6) | First | -- |
| Saturday, August 25 |
| » Lost to Braves (65-64), 3-2 | Wrigley Field (41-23) | 75-53 | |
| » W: Rick Mahler (9-8) L: Scott Sanderson (6-4) | First | -- |
| Sunday, August 26 |
| » Defeated Braves (65-65), 5-0 | Wrigley Field (42-23) | 76-53 | |
| » W: Steve Trout (12-5) L: Pascual Perez (11-6) | First | -- |
| Tuesday, August 28 |
| » Defeated Reds (54-77), 5-2 | Wrigley Field (43-23) | 77-53 | Won 2 |
| » W: Dennis Eckersley (12-11) L: Andy McGaffigan (3-6) S: George Frazier (4) | First | -- |
| » Defeated Reds (54-78), 5-2 | Wrigley Field (44-23) | 78-53 | Won 3 |
| » W: Dick Ruthven (4-9) L: Frank Pastore (3-8) S: Rich Bordi (4) | First | -- |
| Wednesday, August 29 |
| » Defeated Reds (54-79), 7-2 | Wrigley Field (45-23) | 79-53 | Won 4 |
| » W: Rick Sutcliffe (17-6) L: Jeff Russell (6-15) | First | -- |
| Thursday, August 30 |
| » Defeated Braves (65-68), 8-3 | Atlanta-Fulton County Stadium (2-1) | 80-53 | Won 5 |
| » W: Lee Smith (9-4) L: Gene Garber (2-4) | First | -- |
| Friday, August 31 |
| » Lost to Braves (66-68), 3-2 | Atlanta-Fulton County Stadium (2-2) | 80-54 | |
| » W: Donnie Moore (3-3) L: Lee Smith (9-5) | First | -- |
| Saturday, September 1 |
| » Defeated Braves (66-69), 4-1 | Atlanta-Fulton County Stadium (3-2) | 81-54 | |
| » W: Rich Bordi (5-1) L: Craig McMurtry (8-14) S: Lee Smith (27) | First | -- |
| Sunday, September 2 |
| » Defeated Braves (66-70), 4-2 | Atlanta-Fulton County Stadium (4-2) | 82-54 | Won 2 |
| » W: Dick Ruthven (5-9) L: Rick Mahler (9-9) S: Lee Smith (28) | First | -- |
| Monday, September 3 |
| » Defeated Phillies (73-63), 4-3 | Veteran's Stadium (5-3) | 83-54 | Won 3 |
| » W: George Frazier (7-4) L: Renie Martin (1-2) S: Lee Smith (29) | First | -- |
| Tuesday, September 4 |
| » Defeated Phillies (73-64), 7-2 | Veteran's Stadium (6-3) | 84-54 | Won 4 |
| » W: Scott Sanderson (7-4) L: Steve Carlton (11-7) | First | -- |
| Wednesday, September 5 |
| » Lost to Expos (68-70), 3-1 | Stade Olympique (3-5) | 84-55 | |
| » W: David Palmer (6-3) L: Steve Trout (12-6) S: Rick Grapenthin (2) | First | -- |
| Thursday, September 6 |
| » Defeated Expos (68-71), 4-1 | Stade Olympique (4-5) | 85-55 | |
| » W: George Frazier (8-4) L: Charlie Lea (15-10) S: Lee Smith (30) | First | -- |
| Friday, September 7 |
| » Lost to Mets (79-62), 10-0 | Shea Stadium (3-4) | 85-56 | |
| » W: Dwight Gooden (15-8) L: Dick Ruthven (5-10) | First | -- |
| Saturday, September 8 |
| » Defeated Mets (79-63), 6-0 | Shea Stadium (4-4) | 86-56 | |
| » W: Rick Sutcliffe (18-6) L: Walt Terrell (10-11) | First | -- |
| Sunday, September 9 |
| » Lost to Mets (80-63), 5-1 | Shea Stadium (4-5) | 86-57 | |
| » W: Ron Darling (12-6) L: George Frazier (8-5) | First | -- |
| Monday, September 10 |
| » Defeated Phillies (74-69), 3-2 | Wrigley Field (46-23) | 87-57 | |
| » W: Tim Stoddard (9-5) L: Jerry Koosman (14-12) S: Lee Smith (31) | First | -- |
| » Major-league debuts: Billy Hatcher (Cubs) |
| Tuesday, September 11 |
| » Lost to Phillies (75-69), 6-3 | Wrigley Field (46-24) | 87-58 | |
| » W: Charles Hudson (9-10) L: Lee Smith (9-6) S: Al Holland (29) | First | -- |
| Former Cub Paul Carter dies in Lake Park, GA at the age of 91. |
| Wednesday, September 12 |
| » Defeated Expos (71-74), 11-5 | Wrigley Field (47-24) | 88-58 | |
| » W: Tim Stoddard (10-5) L: Bryn Smith (11-12) | First | -- |
| Thursday, September 13 |
| » Major-league debuts: John Christensen (Mets) |
| Friday, September 14 |
| » Defeated Mets (81-67), 7-1 | Wrigley Field (48-24) | 89-58 | Won 2 |
| » W: Rick Sutcliffe (19-6) L: Ron Darling (12-7) | First | -- |
| Saturday, September 15 |
| » Defeated Mets (81-68), 5-4 | Wrigley Field (49-24) | 90-58 | Won 3 |
| » W: Scott Sanderson (8-4) L: Sid Fernandez (4-6) S: Lee Smith (32) | First | -- |
| Sunday, September 16 |
| » Lost to Mets (82-68), 9-3 | Wrigley Field (49-25) | 90-59 | |
| » W: Bruce Berenyi (12-13) L: Steve Trout (12-7) | First | -- |
| Tuesday, September 18 |
| » Lost to Pirates (66-85), 6-2 | Wrigley Field (49-26) | 90-60 | Lost 2 |
| » W: John Tudor (10-11) L: Dennis Eckersley (12-12) S: Don Robinson (9) | First | -- |
| Wednesday, September 19 |
| » Lost to Pirates (67-85), 11-6 | Wrigley Field (49-27) | 90-61 |
