Downey (30) who had a previous stint with Munster (06/07), joined Northampton Saints at the start of the 2007/2008 season and quickly established himself as a regular in their match day squad. In November 2010 he made his 100th appearance for the club and to date has made 135 appearances scoring 12 tries.
A Churchill Cup winner with Ireland in June 2009 he began his career in Leinster before moving to Connacht for two seasons and now returns to Munster on a 2 year contract.
Commenting on the news Tony McGahan said. " James is a quality player who has been on our radar for some time now. We've seen at first hand, on several occasion in recent times in the Heineken Cup exactly what he has to offer and believe that his style and his attitude can only enhance our squad."