The song was released as a single in most European territories and the US, and was a number one hit in France. It was re-recorded for The Mix album in 1991.
"Radioactivity" has remained a regular part of Kraftwerk's live sets over the years. On its original performances in 1976, the band tried out an experimental light-beam operated "percussion cage", where Wolfgang Flür attempted to trigger electronic drum sounds by interrupting light beams using arm gestures. This system was temperamental and frequently failed.
The original recording features an insistent Minimoog bass line (playing eighth notes), with chords played on the distinctive "choir" disc of the Vako Orchestron. Morse code signals spelling out "R-A-D-I-O-A-C-T-I-V-I-T-Y" are also present, near the beginning of the track and again near the end. The second time it is followed by "I-S I-N T-H-E A-I-R F-O-R Y-O-U A-N-D M-E".
Lyrically, the 1975 version of the song plays upon the meaning of its title, with the line "Discovered by Madame Curie" juxtaposed with "Tune in to the melody". While the original does not offer a value judgement on the safety of radioactivity, the 1991 version drops all references to radio and incorporates additional lyrics with a pointed anti-nuclear theme, remaking the central lyrical hook as "stop radioactivity" and also referring to "contaminated population" and mentioning by name Chernobyl, Harrisburg (Three Mile Island), Sellafield and Hiroshima. The band performed it at the "Stop Sellafield" concert in 1992. It was further remixed, for subsequent single release, by William Orbit and François Kevorkian. The song was performed during Kraftwerk's set at Coachella to commemorate the anniversary of the Chernobyl incident on April 26 (the date of the band's performance). In 2012, Kraftwerk performed the new remix of Radioactivity during No Nukes 2012, held in Japan. To commemorate the Fukushima Daiichi nuclear disaster, they sung the song in Japanese, with notable lyric changes such as "Chernobyl, Harrisburg, Sellafield, Fukushima".