This is a list of singles that reached number one on the Cash Box Top 100 Singles chart in 1991, presented in chronological order.
| Issue Date | Song | Artist |
| January 5 | "Justify My Love" | Madonna |
| January 12 | "Justify My Love" | Madonna |
| January 19 | "Justify My Love" | Madonna |
| January 26 | "Love Will Never Do (Without You)" | Janet Jackson |
| February 2 | "The First Time" | Surface |
| February 9 | "Gonna Make You Sweat (Everybody Dance Now)" | C+C Music Factory featuring Freedom Williams |
| February 16 | "Gonna Make You Sweat (Everybody Dance Now)" | C+C Music Factory featuring Freedom Williams |
| February 23 | "All the Man That I Need" | Whitney Houston |
| March 2 | "All the Man That I Need" | Whitney Houston |
| March 9 | "One More Try" | Timmy T |
| March 16 | "Someday" | Mariah Carey |
| March 23 | "Someday" | Mariah Carey |
| March 30 | "Coming Out of the Dark" | Gloria Estefan |
| April 6 | "Coming Out of the Dark" | Gloria Estefan |
| April 13 | "I've Been Thinking About You" | Londonbeat |
| April 20 | "Baby Baby" | Amy Grant |
| April 27 | "Baby Baby" | Amy Grant |
| May 4 | "Baby Baby" | Amy Grant |
| May 11 | "Joyride" | Roxette |
| May 18 | "Here We Go" | C + C Music Factory Featuring Freedom Williams & Zelma Davis |
| May 25 | "Rhythm of My Heart" | Rod Stewart |
| June 1 | "I Don't Wanna Cry" | Mariah Carey |
| June 8 | "More Than Words" | Extreme |
| June 15 | "More Than Words" | Extreme |
| June 22 | "Rush Rush" | Paula Abdul |
| June 29 | "Rush Rush" | Paula Abdul |
| July 6 | "Rush Rush" | Paula Abdul |
| July 13 | "Unbelievable" | EMF |
| July 20 | "Unbelievable" | EMF |
| July 27 | "Right Here, Right Now" | Jesus Jones |
| August 3 | "(Everything I Do) I Do It for You" | Bryan Adams |
| August 10 | "(Everything I Do) I Do It for You" | Bryan Adams |
| August 17 | "(Everything I Do) I Do It for You" | Bryan Adams |
| August 24 | "(Everything I Do) I Do It for You" | Bryan Adams |
| August 31 | "(Everything I Do) I Do It for You" | Bryan Adams |
| September 7 | "(Everything I Do) I Do It for You" | Bryan Adams |
| September 14 | "The Promise of a New Day" | Paula Abdul |
| September 21 | "The Promise of a New Day" | Paula Abdul |
| September 28 | "I Adore Mi Amor" | Color Me Badd |
| October 5 | "I Adore Mi Amor" | Color Me Badd |
| October 12 | "Emotions" | Mariah Carey |
| October 19 | "Emotions" | Mariah Carey |
| October 26 | "Romantic" | Karyn White |
| November 2 | "Romantic" | Karyn White |
| November 9 | "Can't Stop This Thing We Started" | Bryan Adams |
| November 16 | "Cream" | Prince and the New Power Generation |
| November 23 | "Cream" | Prince and the New Power Generation |
| November 30 | "When a Man Loves a Woman" | Michael Bolton |
| December 7 | "When a Man Loves a Woman" | Michael Bolton |
| December 14 | "It's So Hard to Say Goodbye to Yesterday" | Boyz II Men |
| December 21 | "It’s So Hard to Say Goodbye to Yesterday" | Boyz II Men |
| December 28 | "Black or White" | Michael Jackson |
Famous quotes containing the words list of, top, number-one, box, cash and/or list:
“I made a list of things I have
to remember and a list
of things I want to forget,
but I see they are the same list.”
—Linda Pastan (b. 1932)
“Name me, if you can, a better feeling than the one you get when you’ve half a bottle of Chivas in the bag with a gram of coke up your nose and a teenage lovely pulling off her tube top in the next seat over while you’re doing a hundred miles an hour in a suburban side street.”
—P.J. (Patrick Jake)
“I’m your number-one fan.”
—William Goldman (b. 1931)
“I walked on the banks of the tincan banana dock and sat down under the huge shade of a Southern Pacific locomotive to look at the sunset over the box house hills and cry.”
—Allen Ginsberg (b. 1926)
“The Church has always been willing to swap off treasures in heaven for cash down.”
—Robert Green Ingersoll (1833–1899)
“Weigh what loss your honor may sustain
If with too credent ear you list his songs,
Or lose your heart, or your chaste treasure open
To his unmastered importunity.”
—William Shakespeare (1564–1616)