"When You Were Mine" is a song written and released by Prince on his 1980 album, Dirty Mind. Though not released as a single, the song received a promotional 12" release (which included "Gotta Broken Heart Again" and "Uptown"). "When You Were Mine" was later the B-side for Prince's "Controversy" single in 1981.

Prince has performed the song many times in concert, and a live version was included on his 2002 live album, One Nite Alone... Live!. The original studio version was also included on The Hits/The B-Sides in 1993. Prince said he was inspired to write the rock song while listening to John Lennon. The track includes a Farfisa-inspired organ sound played on an Oberheim OB-X.

Cyndi Lauper's mid-tempo ballad cover version of "When You Were Mine" is also synthesizer-based for her 1983 debut album, She's So Unusual. Lauper recorded the song with the original lyrics, casually indicating and accepting the bisexuality of the ex-partner being sung about. She performed the single at the 1985 American Music Awards. It was released exclusively as a promotional single in the United States and received a commercial release in Canada and Japan.

Iain Matthews and David Surkamp's Seattle-based band Hi-Fi were the first to record a cover version of the song, for their 1981 album Moods for Mallards. The version features Matthews on lead vocals. It was released on CD in 2006 by Blue Rose Records on the compilation, Hi-Fi: Complete Works.

In 1983, Mitch Ryder released his cover of "When You Were Mine" as a single. It was also a track on his album Never Kick a Sleeping Dog. The single featured production work by John Mellencamp and was released on his record label, Riva Records. The track received some airplay in the United States and charted on the Billboard Hot 100. The video starred Kitten Natividad. Ryder's version also appeared in the 1984 film Hot Dog... The Movie.

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