These are the number-one singles of 1978 according to the Top 100 Singles in Cash Box Magazine
| The yellow background indicates the #1 song of 1978. |
| Issue date | Song | Artist |
|---|---|---|
| January 7 | Bee Gees | |
| January 14 | Player | |
| January 21 | ||
| January 28 | Randy Newman | |
| February 4 | Bee Gees | |
| February 11 | ||
| February 18 | ||
| February 25 | ||
| March 4 | Andy Gibb | |
| March 11 | Emotion | Samantha Sang |
| March 18 | Bee Gees | |
| March 25 | ||
| April 1 | ||
| April 8 | ||
| April 15 | ||
| April 22 | ||
| April 29 | ||
| May 6 | ||
| May 13 | Yvonne Elliman | |
| May 20 | Paul McCartney & Wings | |
| May 27 | ||
| June 3 | Andy Gibb | |
| June 10 | ||
| June 17 | ||
| June 24 | ||
| July 1 | ||
| July 8 | ||
| July 15 | Gerry Rafferty | |
| July 22 | ||
| July 29 | Rolling Stones | |
| August 5 | ||
| August 12 | Commodores | |
| August 19 | ||
| August 26 | ||
| September 2 | ||
| September 9 | Grease | Frankie Valli |
| September 16 | A Taste Of Honey | |
| September 23 | ||
| September 30 | ||
| October 7 | Exile | |
| October 14 | ||
| October 21 | Nick Gilder | |
| October 28 | ||
| November 4 | ||
| November 11 | Donna Summer | |
| November 18 | ||
| November 25 | Barbra Streisand & Neil Diamond | |
| December 2 | ||
| December 9 | ||
| December 16 | Chic | |
| December 23 | ||
| December 30 |