Chicago is a musical, first performed in 1975, based on the play Chicago by Maurine Dallas Watkins. Its book was by Bob Fosse and Fred Ebb, music by John Kander, and lyrics by Fred Ebb.

The play Chicago was Watkins' retelling of two very public trials for murder that occurred in Chicago in 1924, those of Beulah Annan and Belva Gaertner. Watkins had been a reporter for the Chicago Tribune and later wrote a play based on her coverage.

Gwen Verdon read the play and asked her ex-husband Bob Fosse about the possibility of creating a musical based on it. Fosse approached Watkins for permission to adapt her play but was consistently refused. He obtained the rights from her estate following her death in 1969 leading to the development of Chicago: A Musical Vaudeville, which made the play's comparison between "justice" and "show-business" explicit by conceptualizing the plot as a series of vaudeville acts.

The play was produced in 1975, starring Chita Rivera as Velma Kelly, Gwen Verdon as Roxie Hart, and Jerry Orbach as Billy Flynn. Liza Minnelli served as a replacement for Gwen Verdon for a month in 1975, and her Broadway "comeback" generated publicity which helped lengthen the run of the show. When Verdon left the show, Fosse's girlfriend Ann Reinking stepped into the role.

The show was revived in 1996, being directed by Walter Bobbie and choreographed "in the style of Bob Fosse" by Ann Reinking, and starring Joel Grey, James Naughton, Bebe Neuwirth, and Ann Reinking. This version was still running as of March2005.

The musical was adapted for the movie Chicago in 2002, starring Renée Zellweger as Roxie and Catherine Zeta-Jones as Velma (Zeta-Jones won a Best Supporting Actress Oscar for the role} The story was told by staging the vaudeville acts as fantasies of Roxie Hart, by eliminating some songs, and by changing the role of Mary Sunshine from male to female.

The 2002 film won the Oscar for Best Picture

The Numbers and the Vaudeville acts they were modelled on

• "Overture" - performed by a pit-band
• "All That Jazz" - a number in homage to famous speakeasy performer Texas Guinan
• "Funny Honey" - modeled on Helen Morgan, singing "Bill"
• "Cell Block Tango" - the "merry murderesses" evoke the "ethnic numbers" of Vaudeville, and the death by hanging is staged as a "tightrope" act
• "When You're Good to Mama" - a "Sophie Tucker"-type double-entendre song, hingeing on the perceived homosexuality of the character
• "All I Care About" - a striptease based on Sally Rand and her fan dance, with the performer modeled on clarinetist and bandleader Ted Is Everybody Happy? Lewis
• "Little Bit of Good" - a female-impersonator reminiscent of Julian Eltinge singing a Jerome Kern parody as Marilyn Miller
• "We Both Reached for the Gun" - a ventriloquist act
• "Roxie" - an autobiographical, observational stand-up comedy routine
• "I Can't Do It Alone" - half of a "double-act" (or an acrobatic "sister-act")
• "My Own Best Friend" - a torch song, subverted by the fact the singers are praising themselves
• "Me and My Baby" - a cakewalk, a la Eddie Cantor
• "Mr. Cellophane" - a clown number reminiscent of Bert Williams' 1915 Follies song "Nobody" performed wearing the costume of Emil Jannings from the final scene of The Blue Angel
• "When Velma Takes the Stand" - evokes vaudeville's courtroom comedy sketches, and staged as a parody of Rudy Vallee's numbers featuring collegiate chorus boys with megaphones
• "Razzle Dazzle": the lawyer Billy Flynn assumes the persona of Clarence Darrow in a juggling circus act.
• "Class"
• "Nowadays" - in the style of bandleader Ted Lewis
• "Hot Honey Rag" - in the style of bandleader Ted Lewis
• "All That Jazz"