"What a Fool Believes" is a song written by Michael McDonald and Kenny Loggins. The best-known version was recorded by The Doobie Brothers (with McDonald singing lead vocals) for their 1978 album Minute by Minute. The single reached number one on the Billboard Hot 100 on April 14, 1979, remaining in that position for one week.^[3] The song received Grammy Awards in 1980 for both Song of the Year and Record of the Year.

"What a Fool Believes" was one of the few non-disco No. 1 hits on the Billboard Hot 100 during 1979. The song lyrics tell a story of a man who is reunited with an old love interest of his and attempts to rekindle a romantic relationship with her he never realized didn't exist.

Michael Jackson claimed to have contributed at least one backing track to the original Doobie Brothers recording, but was not credited for having done so.^[4]

Loggins released a version of the song (five months prior to The Doobie Brothers) on his 1978 album Nightwatch, and a live version on his 1980 album Kenny Loggins Alive.

There is a Loggins/McDonald live duet on Loggins' 1993 album Outside: From the Redwoods.^[5]

Warner Brothers also released a 12" single disco version by The Doobie Brothers (backed with "Don't Stop to Watch the Wheels"). Mixed by disco producer Jim Burgess, at 5:31 the song is considerably longer than the 3:41 versions on the 7" single and the Minute by Minute LP. The 12" version also has a more pronounced bass-driven drumbeat.^[6][7]

Live versions of the song often feature a guitar bridge after the second verse.

"What a Fool Believes" is a 12" vinyl EP by Matt Bianco, released in 1991.

• A. "What a Fool Believes" (Mixed by Bobby Summerfield)
• B1. "Samba in Your Casa" (Cashassa Mix) (Mixed by Bobby Summerfield)
• B2. "Say It's Not Too Late"

Numerous cover versions of the song have been recorded, including:

• 1980: Aretha Franklin - from the album Aretha^[8]
• 1991: George Michael - from Live In Birmingham, a 1991 live bootleg^[9]
• 1996: Compilation album Romantic Guitars: Amour
• 1997: The Wades - from The Feel Good Factor^[10]
• 1998: M People - from The Best of M People (also on 1999 album Testify)
• 1998: Peter Cox - from Peter Cox
• 1999: Aretha Franklin - from Greatest Hits^[8]
• 2000: Self - from Gizmodgery, a record which was recorded entirely with toy instruments
• 2000: Dionne Warwick - from Dionne Sings Dionne Vol.2
• 2004: Courtney Murphy - Australian Idol 2004
• 2007 Carol Welsman - from the CD Carol Welsman
• 2007: Lackthereof^[11] - from Bridging the Distance: a Portland, OR covers compilation
• 2008: Neri per Caso & Mario Biondi - from the album Angoli diversi
• 2010: The Idea of North and James Morrison - from the album Feels Like Spring
• 2010: Justin Mauriello - from the album Justin Sings the Hits

While not a cover version, the 1980 hit "Steal Away" by Robbie Dupree is built around a keyboard riff which is notably similar to that of the Doobie Brothers hit. Another hit song that has a very strong reference to some of the keyboard riffs and vocal melodies of "What A Fool Believes" is the 1980 Ronnie Milsap hit "If You Don't Want Me" that spawned the popular line dance 'The Freeze'.

• A fictional account of the creation of this song was featured in the first episode (June 2005) of Yacht Rock, an Internet series featuring characters of Michael McDonald and the Doobies. In the parody, Kenny Loggins inspires McDonald to write the song after Doobie guitarist Jeff "Skunk" Baxter threatens to kick McDonald out of the band unless he writes a hit song for them.
• The song was used in "The Monkey Suit", the 21st episode of the 17th season (14 May 2006) of The Simpsons TV show. It was used as background music for an animatronic representation of biblical creation theory.
• The song was used in several Stella shorts, including "Whiffleball," "Audition" and "Poker."
• The song was featured on the original movie soundtrack of Frankie and Johnny.
• A cover of the song was featured on an episode of the television show 30 Rock entitled "St. Valentine's Day".
• The song was featured in Jeremy Clarkson's Top Gear review of the E60 BMW M5.
• A cover of Petula Clark's "Downtown" on the Canadian sketch comedy series SCTV includes a variation of the beginning of "What a Fool Believes". A Michael McDonald impersonator sings backup in the song.
• Another Michael McDonald lookalike sings the song's melody with different words in the Late Night with Conan O'Brien sketch "The Camp Michael McDonald Channel". The McDonald impersonator also sings different words to the tune of "Takin' It to the Streets" and McDonald's solo hit "Sweet Freedom".
• MF Doom sampled the song in "Mandrake", an instrumental beat on his "Metalfingers Presents: Special Herbs, The Box Set" collection.
• The Doobie Brothers performed the song as the musical guests on the 27 January 1979 episode of Saturday Night Live (season 4).
• The song was used in the movie "Personal Best." Vincent Canby's reference to "not great pop music" appearing on the soundtrack in his New York Times review is likely about this song.

An unrelated song with the same title, written by Kavon Shah, C Ridenhour, K Bryant Jackson and Veda, appeared on the 2005 Public Enemy album, New Whirl Odor.