It is likely to expand its digital offering to include ebooks, films and games online in coming months.
All customers will get their first download for free and Sainsbury’s will offer Nectar loyalty points with purchases.
Sainsbury’s will offer 2.3 million tracks for download including individual songs and albums.
Single tracks will start at 89p and chart albums from £6.99. It will also offer a deal of the week with albums for £4.99. Apple’s iTunes offers single tracks from 59p to 99p.
The supermarket is also guaranteeing the cheapest price for all pre-order tracks and albums and will refund the difference if the price falls between pre-order and release.
Customers can also preview music before purchase via its playlist function.
Mark Bennett, head of entertainment online, says: “This launch of our new MP3 music service enables our customers across the UK to get digital music at great value. This is the first step in our expansion to offer digital entertainment alongside our existing range of CDs, Games, Film and books catalogue.”
Entertainment retailer Dixons recently launched a movie streaming service in a bid to complement its electricals business with a content platform and Tesco already offers digital versions of DVD’s bought at its stores.