"I Want to Know What Love Is" is a 1984 power ballad recorded by the British-American rock band Foreigner. The song hit #1 in both the UK and the U.S. and is the band's most successful single. It remains one of the band's best known songs and most enduring radio hits, charting in the top 25 in 2000, 2001 and 2002 on the BillboardHot Adult Contemporary Recurrents chart.

Written by Mick Jones, with some degree of uncredited contribution by Lou Gramm, and produced by Jones and Alex Sadkin, it was the first single released from the album Agent Provocateur(1984). The song features backing vocals from the New Jersey Mass Choir (of the GMWA), Dreamgirlsstar Jennifer Holliday, and the Thompson Twins. The choir appears in the song's music video.

"I Want to Know What Love Is" reached number one in the UK Singles Charton January 15, 1985, and stayed there for three weeks. It reached the top of the U.S. BillboardHot 100 on February 2, 1985, where it stayed for two weeks. It was Foreigner's first and only Pop chart-topper in either country, although the band had four #1 Mainstream Rock and one #1 Adult Contemporary radio hits in the U.S. This was the band's third of four #1 singles on the Mainstream Rock chart. The song spent five weeks at #1 in Australia, and also hit the top of the charts in Canada, Norway and Sweden, peaking at #2 in Switzerland and South Africa.

The song was also issued as a 12" single with a slightly longer time length of 6:23. This version contains a slightly longer intro and an extended vocal chorus/ad-lib-to-fade ending.

The single's B-Side, "Street Thunder (Marathon Theme)", is an instrumental track originally appearing on The Official Music of the XXIIIrd Olympiad—Los Angeles 1984, and later on the band's 2-CD compilation, Jukebox Heroes: The Foreigner Anthology, in 2000.

Soon after Foreigner's single topped the charts, the New Jersey Mass Choir released its own, similar-sounding version of the song, on an album also titled I Want to Know What Love Is. Their single peaked at #37 on the Hot Black Singles chart and #12 on the Hot Dance Music/Maxi-Singles Sales chart.

The Foreigner song was ranked by Billboardas the number four Hot 100 single of the year 1985. It was the band's fourth Gold single in the U.S. and their first and only Gold single in the UK.

In 2004 "I Want to Know What Love Is" was voted #476 on Rolling Stone's list of the 500 greatest songs of all time. In 2006 this song was included on VH1's program "Top 100 Songs of the 80's" at #65.

The song was used on the 16th episode of Miami Vicein the first season, entitled Rites of Passageon 8 February 1985. The song was made part of the videogame Grand Theft Auto: Vice City Storiessoundtrack in 2006, and was the background music for the game's first trailer and intro cutscene. In 2007, the game SingStar '80sincluded the song. The song was played in a scene in Larry The Cable Guy: Health Inspectorand in the "Valentine's Day" episode of the TV show Ed. The song also features in the 1998 Swedish film Show Me Love. The song was sung twice on General Hospitalin 2009; first by the character Spinelli to his girlfriend Maxie at Jake's karaoke night, and second by guests at a reception, to Spinelli and Maxie. The song appears in Alvin and the Chipmunks: The Squeakquel.

"I Want to Know What Love Is" was covered by Australian singer Tina Arena and her recording was released as a single in 1998 from her album In Deep. Arena's version of the song was produced by Foreigner band member Mick Jones, who was the song's writer.

The song peaked at #13 in France and finished 60th on the End Of Year Chart (1999).

"I Want to Know What Love Is" was covered by American singer Mariah Carey and released as the second single from her twelfth studio album, Memoirs of an Imperfect Angel(2009). The single, produced by Carey, C. "Tricky" Stewart and James "Big Jim" Wright, was sent to European radio stations on August 28 and official impacted U.S. radio on September 14, 2009. Mick Jones said of her version: "I think she's actually retained the integrity of the song. You know, the arrangement is very similar to the original. They haven't tampered with the song too much. She's captured a certain emotional thing, a feeling."

The single has garnered generally positive reviews; Australian magazine "Rhyme & Reason" stated that "[While Carey stayed] [...] true to the original, this piano-led remake is less an overhaul of the classic '80s hit than it is a modest but impressive update." The UK Daily Stargave it a 5 out of 5 rating: "[The song is] given the Carey treatment and [is] complete with choir and karaoke climax. It's a great rework." Bill Lamb from About.com said that "Mariah Carey's new version could leave you speechless. The diversity of vocal coloring expressed in this recording is stunning. While the single Obsessed remains disappointing, this single is a reminder of just how formidable Carey's talents are given a strong production and arrangement". Los Angeles Timessaid "[T]ackling a well-known power ballad seems like a safe choice. It's a comfortable fall-back plan after "Obsessed" performed well, but did far from blockbuster numbers. It will undoubtedly be a hit, but it's giving me more reason to fear Imperfect Angel.The sort-of-real/sort-of-not feud with Eminem seemed largely a ploy to keep Carey in the headlines, and covering Foreigner seems just as calculated to steer Carey back onto familiar ground". Entertainment Weeklysaid "Mariah + Gospel Choir + "I Want to Know What Love Is" = Ecstasy".

The single received a negative review from Alex Fletcher of UK-based entertainment site Digital Spy: "With its corny lyrics, choir backing vocals and sweeping, jumbo jet-size chorus, ["I Want to Know What Love Is"] may as well have been written for Mimi. However it's more than a little disappointing, that her take on the Foreigner classic is so timid. The singer gives an understated performance with only a few piano flourishes and robotic beats as backing. When she does finally unleash her trademark whistle for the crescendo, it feels too calculated and sounds like a recording studio clip chucked on the end. She has stripped away the much-loved ridiculousness and pomposity of the original, leaving a rather limp, lifeless number in its place.

Carey filmed a music video for "I Want to Know What Love Is" in September 2009 in New York City. The director for the video is Hype Williams. The video premiered on Mariah's official website on November 13, 2009. The video shows Carey singing in a stadium whilst shots are intercut with people accompanied by their loved ones, or who have had tough times in their past (i.e. terminal illness etc) who get quite emotional watching her perform. A gospel choir appears at the end of the video singing along with Carey at the centre of the stadium. In the video, Mariah adopts her signature curly hairstyle that was present in the initial stages of her career from 1990–1993, maintaining the 'Memoirs' theme of the new album.

"I Want to Know What Love Is" debuted on the Hot 100 at #66 for the week ending October 3, 2009, eventually peaking at #60. In Brazil, it reached number one on the five-month-old Brazilian Airplay Chart in December and remained at the top spot for the next two charts, spanning all of January and February. The song also reached #1 on the Japanese airplay chart as well as #19 on the UK Official Top 40, as well as #3 on the Japan Hot 100. The song reached the Top 10 on the U.S. BillboardAdult Contemporary Tracks chart at #10, bringing Carey's total number of top ten hits on that chart to 20, one behind Celine Dion's current record. On the UK Singles Chart, the song debuted at #19 on the week ending November 29, becoming her highest debuting and peaking song since 2008's "Touch My Body", which peaked at #5. The song has debuted at #6 in France selling 1,910 copies in its first week.

Laura Branigan and John Farnham performed a duet to the song on live television for the 1986 Logie Awards, an Australian awards show.

In 1997 this song was also covered by slain South African reggae star Lucky Dube on his Taxman album. It featured strong South African reggae drum beats by ace drummer Mnca Mtshali.

A Spanish-language version by The Barrio Boyzz, entitled "Quiero Saber Que Es Amor/I Want to Know What Love Is", hit #40 on Billboard'sLatin Tropical/Salsa Airplay chart on April 7, 2001.

In 2001, singer Rhona covered it on her debut self-titled album.

A cover by Gloria Gaynor appears on the 2002 K-Tel compilation Tina Turner & Gloria Gaynor, Back To Back.

In 2002 the victims of fires in a disco in Sweden and a bar in The Netherlands recorded this song as a way for these young people to learn to cope with their memories and their injuries. Their single, released under the artist name Volendam meets Göteborg, reached #39 in the Dutch charts.

In 2003 Wynonna Judd's cover of "I Want to Know What Love Is" was released as a single from her album What the World Needs Now Is Love, peaking at #14 on the Billboard Hot Adult Contemporary chart. Later that year, the track was remixed for dance clubs, peaking at #12 on Billboard'sHot Dance Airplay chart in 2005.

In 2004, a cover by Sarah Geronimo from her album Sweet Sixteenwas a hit in her native Philippines.

The song was one of several covers chosen by Clay Aiken to appear on his 2006 album A Thousand Different Ways.

In 2008 this song was covered by David Phelps on his album The Voice.

The song was also performed by Celtic Thunder's Keith Harkin in concert, and it appears on that band's 2008 album Act Two.

Alvin and the Chipmunks covered the song for the 2009 movie Alvin and the Chipmunks: The Squeakqueland its soundtrack.

Leela James covered the song on her 2009 sophomore release "Let's Do It Again".

Other covers of this song have been recorded by familiar artists as diverse as Progressive rock keyboardist Geoffrey Downes, pop chanteuses Rita Coolidge and Shirley Bassey, Latin crooner Julio Iglesias, Memphis soul singer Ann Peebles and Christian pop artist Kathy Troccoli.