The 27-year old striker has agreed a deal with the Tractor Boys and the transfer is now complete, seeing him depart Cardiff following two loan spells and a permanent stay since 2009.
"I enjoyed my time at Cardiff but this is a new start for me at Ipswich and I'm looking forward to it," he told the club's official website.
"I spoke to the manager and was impressed with his plans for the club. I know some of the players here as well and from talking to them, it was clear there is real ambition at Ipswich.
"I can't wait to get going and the target is to help the club reach the Premier League."