Amazon's MP3 store offers 22 million songs in the US and more than 29 million globally.
Amazon has launched a new digital music store specifically for Apple iPhone and iPod touch devices.
Users can access the MP3 music store through Safari web and choose from a list of 22 million songs available in the US.
Songs can be saved to Amazon cloud player libraries, which users can download or play from.
Amazon Music vice president Steve Boom said that since the launch of the Cloud Player app for the iPhone and iPod touch, consumers have been requesting to buy music from Amazon directly from their devices.
"For the first time ever, iOS users have a way do that -- now they can access Amazon's huge catalog of music, features like personalized recommendations, deals like albums for $5, songs for $0.69, and they can buy their music once and use it everywhere," Boom said.
The move is expected to allow Amazon to take on Apple, Netflix, Google and Barnes & Noble in developing its business range.
In December 2012, Amazon launched an instant-video app that allows users to stream or download Amazon Instant Video movies and TV episodes from the video library onto their iPhone or iPod Touch.