"SOS" was written by J. R. Rotem and E. Kidd Bogart, with additional credit assigned to Ed Cobb for inspiration built around a sample of Soft Cell's 1981 recording of "Tainted Love".

"SOS" was certified triple Platinum by the Recording Industry Association of America (RIAA) for sales and streams of 3,000,000 units.

[3] "SOS" contains a sample of "Tainted Love", written by Ed Cobb in 1964, and popularized by English synthpop duo Soft Cell in 1981.

[3] In an interview with HitQuarters, Rotem explained the song's conception, saying "I heard 'Tainted Love' and wanted to take the bass line and update it with a new swing.

Tan also noted that the background vocals were pitch shifted to increase tonal quality and create an enhanced effect during the chorus.

Tan continued to note that the lack of reverb included on "SOS" was largely due to the fact that being an uptempo dance-pop song, there was not a lot of room left to add anything else.

[11] The song's instrumental composition is built around a prominent sample of "Tainted Love", which was originally written by Ed Cobb in 1965 and popularised by English synthpop duo Soft Cell, when they released their cover version in 1981.

The lyrics reference Cutting Crew's "(I Just) Died in Your Arms," Tears for Fears' "Head over Heels," "You Keep Me Hangin' On" (a popular cover of which was released by Kim Wilde in the 1980s), Michael Jackson's "The Way You Make Me Feel" and "Take On Me," as well as the band that recorded it, a-ha.

[15] The maxi single included both the radio edit and instrumental versions of "SOS", as well as the album track "Break It Off", which features Jamaican reggae singer Sean Paul.

[15] In Australia, the song was released to download digitally through the iTunes Store on April 3, 2006, with non-single track "Let Me" featuring as the B-side.

Bill Lamb of About.com praised the sampling of Cobb's "Tainted Love" and Rihanna's vocal performance, with specific regard to her lower register.

[12] Additionally, Lamb compared Rihanna's vocal performance in the song to Beyoncé, writing "The echoes of Beyonce in the higher register are weaker.

"[12] Sal Cinquemani of Slant Magazine praised the sample and noted that "SOS" rivals Rihanna's debut single "Pon de Replay" (Music of the Sun, 2005).

[20] Despite praising "SOS", Cinquemani continued to write that it was the only song on A Girl Like Me which displayed a high level of "audacity".

"[11] Barry Walters of Rolling Stone wrote, "Barbados-born emigre Rihanna's huge dancehall pop hit last year, "Pon De Replay," was savvy and sexy, and her new smash, "SOS," is even more so.

Singing a snaky Destiny's Child-like melody around synth riffs and machine beats from Soft Cell's '80s classic hit "Tainted Love," Rihanna proves America still appreciates clever pop when it hears it.

[26] The song displaced Daniel Powter"s "Bad Day", which had spent the previous five weeks atop the chart, from number one.

[35] In Switzerland, "SOS" debuted and peaked at number three on May 21, 2006, and stayed inside the top-ten of that countries singles chart for the following nine weeks.

[38] Elsewhere, the song attained top-five positions on the singles charts of Austria and Belgium (Wallonia), peaking at numbers four and five, respectively.

[50] In New Zealand, the song debuted at number 37 on April 10, 2006, and spent the following five weeks fluctuating in the lower region of the top 40 singles.

[57] The video begins with Rihanna singing the hook while wearing a low-cut green dress and dancing in front of tropical trees on an island.

Halfway through the verse, another scene is introduced, with Rihanna wearing a pink dress in a mirrored room, showing multiple reflections of the singer from different angles.

The scene is fairly dark with different colored lights projected into different areas of the nightclub, as dancers infiltrate the dance floor surrounding Rihanna.