The England international has played just one league game and two Champions League games for Atalanta since joining from Everton in the summer for a fee of around 10 million pounds.
"We wanted to add to that area. Ben is a good player and an experienced player. That will be a good boost for us in the second half of the season," Ipswich coach Kieran McKenna said.
Godfrey previously made 93 appearances for Everton after joining the Merseyside club in 2020 from Norwich City.
"I have really enjoyed speaking to the manager and to have the opportunity to work under him now is something I’m very excited about," Godfrey said.
"I’ve watched a lot of the games from the first half of the season and you can tell from those that the group is a tight one, full of players giving everything to achieve their goals."
The centre-back is Ipswich's first signing of the January transfer window as they look to escape the relegation zone, sitting 18th after their 2-2 draw with Fulham on Sunday, despite wins over Tottenham Hotspur and Chelsea in the past two months.
Check out the match report from Ipswich's draw on Sunday with Flashscore.