These are the songs that reached number one on the Top 40 Best Sellers chart (expanded to the Top 50 as of October 13) in 1951 as published by Cash Box magazine. Artists were not specified in the charts of this period so songs may represent more than one version. The artist who most popularized each song is listed.
| Issue date | Song | Artist |
|---|---|---|
| January 6 | "Tennessee Waltz" | Patti Page |
| January 13 | ||
| January 20 | ||
| January 27 | ||
| February 3 | ||
| February 10 | "My Heart Cries For You" | Guy Mitchell |
| February 17 | ||
| February 24 | ||
| March 3 | "Be My Love" | Mario Lanza |
| March 10 | ||
| March 17 | ||
| March 24 | ||
| March 31 | ||
| April 7 | "If" | Perry Como |
| April 14 | ||
| April 21 | "Mockin' Bird Hill" | Patti Page |
| April 28 | ||
| May 5 | ||
| May 12 | ||
| May 19 | "On Top of Old Smoky" | The Weavers |
| May 26 | "Mockin' Bird Hill" | Patti Page |
| June 2 | "On Top of Old Smoky" | The Weavers |
| June 9 | "Too Young" | Nat King Cole |
| June 16 | "How High The Moon" | Les Paul and Mary Ford |
| June 23 | ||
| June 30 | "Too Young" | Nat King Cole |
| July 7 | ||
| July 14 | ||
| July 21 | ||
| July 28 | ||
| August 4 | ||
| August 11 | "Come On-a My House" | Rosemary Clooney |
| August 18 | ||
| August 25 | "Because of You" | Tony Bennett |
| September 1 | "Sweet Violets" | Dinah Shore |
| September 8 | "Come On-a My House" | Rosemary Clooney |
| September 15 | "Because of You" | Tony Bennett |
| September 22 | ||
| September 29 | ||
| October 6 | ||
| October 13 | ||
| October 20 | ||
| October 27 | ||
| November 3 | "(It's No) Sin" | Eddy Howard |
| November 10 | ||
| November 17 | ||
| November 24 | ||
| December 1 | ||
| December 8 | ||
| December 15 | "Down Yonder" | Del Wood |
| December 22 | "(It's No) Sin" | Eddy Howard |
| December 29 |