1978 PGA Championship Winner and Scores
Winner: John Mahaffey, 276
Where it was played: Oakmont Country Club in Oakmont, Pennsylvania
Tournament dates: August 3-6, 1978
Leader after first round: Tom Watson, 67
Leader after second round: Tom Watson, 136
Leader after third round: Tom Watson, 203
Notable Notes: Tom Watson probably should have won this tournament. He led the first three rounds, and had a 5-stroke advantage going into the fourth. But he shot 73 in that final round, opening the door for others. John Mahaffey and Jerry Pate took advantage, tying Watson with rounds of 66 and 68, respectively. (Pate could have won it with a 4-foot putt on the 72nd hole, but missed.) The trio went into a sudden-death playoff, and Mahaffey won it with a birdie on the second extra hole. Watson never won a PGA Championship.
Final Scores
| John Mahaffey | 75-67-68-66—276 |
| Jerry Pate | 72-70-66-68—276 |
| Tom Watson | 67-69-67-73—276 |
| Tom Weiskopf | 73-67-69-71—280 |
| Gil Morgan | 76-71-66-67—280 |
| Craig Stadler | 70-74-67-71—282 |
| Andy Bean | 72-72-70-70—284 |
| Lee Trevino | 69-73-70-72—284 |
| Graham Marsh | 72-74-68-70—284 |
| Fuzzy Zoeller | 75-69-73-68—285 |
| Joe Inman | 72-68-69-77—286 |
| Hale Irwin | 73-71-73-70—287 |
| John Schroeder | 76-69-70-72—287 |
| Larry Nelson | 76-71-70-70—287 |
| Billy Kratzert | 70-77-73-67—287 |
| Grier Jones | 70-73-71-74—288 |
| Ben Crenshaw | 69-71-75-73—288 |
| Phil Hancock | 70-73-70-75—288 |
| Bob Gilder | 74-71-70-74—289 |
| Dave Stockton | 68-75-74-72—289 |
| Wally Armstrong | 71-73-75-70—289 |
| Don January | 73-72-75-69—289 |
| Bobby Nichols | 75-67-73-74—289 |
| Kermit Zarley | 75-71-67-76—289 |
| George Burns | 79-68-70-72—289 |
| Peter Oosterhuis | 73-72-72-73—290 |
| Bob Shearer | 73-73-71-73—290 |
| Hubert Green | 71-71-74-74—290 |
| Bob Zender | 73-69-74-74—290 |
| George Cadle | 74-74-74-68—290 |
| Greg Powers | 75-70-75-70—290 |
| Gary Player | 76-72-71-71—290 |
| Rod Curl | 76-71-73-70—290 |
| Jim Dent | 74-74-70-73—291 |
| Mike Sullivan | 70-75-73-73—291 |
| Lanny Wadkins | 70-73-72-76—291 |
| Victor Regalado | 76-71-70-74—291 |
| Keith Fergus | 71-74-72-75—292 |
| Danny Edwards | 74-73-70-75—292 |
| Morris Hatalsky | 77-71-69-75—292 |
| Johnny Miller | 69-72-72-79—292 |
| Bill Rogers | 72-74-73-74—293 |
| Dave Eichelberger | 74-73-74-72—293 |
| Lee Elder | 71-76-73-73—293 |
| Leonard Thompson | 72-76-74-71—293 |
| Andy North | 76-71-73-73—293 |
| Mike Morley | 70-73-73-77—293 |
| Dewitt Weaver | 75-69-72-77—293 |
| Rod Funseth | 70-73-72-78—293 |
| Tommy Aycock | 74-72-75-73—294 |
| Dave Hill | 69-76-75-74—294 |
| Raymond Floyd | 76-72-73-73—294 |
| Jack Newton | 73-71-71-79—294 |
| Bobby Cole | 75-73-73-74—295 |
| Bobby Wadkins | 74-74-71-76—295 |
| Bob Murphy | 71-75-71-78—295 |
| Tom Purtzer | 72-70-78-75—295 |
| Mike McCullough | 76-71-75-74—296 |
| Jay Haas | 73-71-77-75—296 |
| Curtis Strange | 72-74-71-79—296 |
| George Archer | 76-67-77-77—297 |
| Bruce Lietzke | 75-72-73-78—298 |
| Lon Hinkle | 73-73-74-79—299 |
| Laurie Hammer | 74-72-77-77—300 |
| Gary Koch | 74-72-77-77—300 |
| Howard Twitty | 75-72-77-76—300 |
| Ed Sneed | 76-72-73-79—300 |
| Jerry Heard | 76-71-72-81—300 |
| Jim Colbert | 74-74-73-80—301 |
| Bill Hall | 76-72-77-78—303 |
