The Portuguese participating broadcaster, Rádio e Televisão de Portugal (RTP), internally selected its entry for the contest.

[1] Their highest placing in the contest was sixth, achieved in 1996 with the song "O meu coração não tem cor" performed by Lúcia Moniz.

Their least successful result has been last place, achieved on three occasions, most recently in 1997 with the song "Antes do adeus" performed by Célia Lawson.

[3] On 23 February 2005, the broadcaster announced that José da Ponte, Alexandre Honrado, and Ernesto Leite had been invited to create the song, while its performer would be chosen by RTP.

"Amar", which was composed by Ernesto Leite and José da Ponte with lyrics by Alexandre Honrado, Ernesto Leite and José da Ponte, was planned to be presented to the public on 31 March 2005 during the RTP 70th anniversary show Gala de Aniversário RTP, however the song was presented on 1 April 2005 via the release of the official music video instead.

[5][6] According to Eurovision rules, all nations with the exceptions of the host country, the "Big Four" (France, Germany, Spain and the United Kingdom), and the ten highest placed finishers in the 2004 contest are required to qualify from the semi-final on 19 May 2005 in order to compete for the final on 21 May 2005; the top ten countries from the semi-final progress to the final.