Chúc mừng: 50 năm của cuộc thi ca hát Eurovision

Congratulations: 50 Years of the Eurovision Song Contest was a television programme organised by the European Broadcasting Union (EBU) to commemorate the Eurovision Song Contest's fiftieth anniversary and to determine the contest's most popular entrant of its fifty years. Hosted by Katrina Leskanich and Renārs Kaupers, the event took place at Forum, in Copenhagen, Denmark, on 22 October 2005. The host broadcaster was the Danish Broadcasting Corporation (DR). Fourteen songs from the contest's first half-century, chosen through an internet poll and by a jury, contested the event.

Thirty-one EBU-member countries broadcast the concert (although notably France, Italy, and the United Kingdom did not) and televoting and juries in these countries decided the winner. A total of 2.5 million votes were cast during the live broadcast. The event was won by the song "Waterloo" by group ABBA, who did not attend; the act had originally won the contest for Sweden in 1974.

To coincide with the event, the EBU released two double album CDs featuring Eurovision songs from the previous fifty years. Two DVDs with original Eurovision performances of these songs were also released.