[1] It features guest vocals from Ja Rule (Jeffrey Atkins) and Caddillac Tah (Tiheem Crocker).

Over a reworking of the beat to Craig Mack's "Flava in Ya Ear" (produced by Easy Mo Bee), Lopez sings about "dropping a boyfriend who keeps messing up".

In July 2001, Jennifer Lopez's number-one album J.Lo (2001) was reissued with a Murder Inc. remix of one of its original singles, "I'm Real".

[2] According to Rule, he initially was "just f[uck]ing around" with the track after Lopez's team gave it to him to remix, but it turned out to be "a hell of a record".

[4] Rooney explained: "We had changed the sound of Jennifer Lopez [with "I'm Real"] and we didn't have anything else on the [J.Lo] album we could release as a single.

Ashanti wrote two verses and recorded a demo for the new version of "Ain't It Funny" for Lopez.

"[5] "Ain't it Funny (Murder Remix)" is a hip hop song with a duration of three minutes and forty-nine seconds (3:49).

"[2] Over the reworking of the "Flava In Ya Ear" beat, Lopez sings about "a boyfriend who keeps messing up," while Rule and Cadillac Tah "drop rhymes" on the track.

[1] For the week ending December 29, 2001, "Ain't it Funny" debuted at number 74 on the Billboard Hot 100.

[14] For the week ending February 9, 2002, "Ain't it Funny" jumped from number 12 to ten on the Hot 100 and Airplay chart, making it Lopez's fifth top-ten hit at the time.

[18] Additionally, the song unseated the track "Always On Time" at the summit of the Hot 100, which was coincidentally by Ja Rule featuring Ashanti, two people who worked with Lopez on the remix.

[20] The murder remix for "Ain't it Funny" attained moderate success internationally.

[22] "Ain't it Funny" also peaked at number seven in The Netherlands for the week ending March 30, 2002.

The first part of the video shows Lopez having a small party in her home with guests including Ja Rule and Ashanti.