US-based Apple Computers crossed the billion-song threshold at its internationally popular online iTunes music store.
The billionth song officially sold from the Internet music shop was "Speed of Sound" by the British band Coldplay. It was downloaded by a man in the US state of Michigan, according to Apple.
"I hope that every customer, artist and music company executive takes a moment today to reflect on what we've achieved together during the past three years," Apple chief executive Steve Jobs said in a written release.
"Over one billion songs have now been legally purchased and downloaded around the globe, representing a major force against music piracy and the future of music distribution as we move from CDs to the Internet."
Apple's iTunes store has been the prime vender for audio and video downloads for the company's market-dominating iPod portable MP3 players.
Apple referred to iTunes as the world's most popular video download store, saying it has sold more than 15 million videos.
Apple had sold more than 42 million iPods before recent retail price cuts made the MP3 music player even more affordable.
In the final quarter of 2005, ending with the Christmas holiday, iPod sales averaged about 100 per minute.
In keeping with its enigmatic marketing style, Apple has invited news reporters to its Cupertino, California, headquarters on Tuesday for the unveiling of "some fun new products."