| Song title Bold titles have been released in some form (?) indicates song title unconfirmed (Name) in brackets indicates artist if not credited as ABBA (or Björn & Benny, Agnetha & Frida) | First known recording or performance date (?) indicates date not known or unconfirmed (NR) indicates song not recorded |
| Una voce poco fa | 8 May 1978 |
| Una voce poco fa | November 1979 |
| Under Attack | 2 August 1982 |
| Under Attack (instrumental) | February 2007 |
| Under Attack (single remix) | 13 November 1982 |
| Under Attack (TV version) | 23-29 September 1982 |
| Underbar | 4 September 1981 |
| Under My Sun | 10 August 1979 (?) |
| (Untitled) | 24 September 1973 |
| (Untitled jam) | circa September – November 1979 (?) |
ABBA Omnibus 