The Fashion Police star decided to have the procedure to combat her chances of further illness after being diagnosed with breast cancer earlier this year.
Husband Bill Rancic has since told E! News that Giuliana is recovering well after Tuesday's surgery and is already getting back to her old self.
"G is doing really well. Her surgery lasted about four hours and the doctors were very pleased with the result," Bill explained.
"She had a little bit of pain through the night but is feeling much better this morning and was cracking jokes."
Giuliana also shared her own message to be passed on, saying: "I want to thank all the viewers and fans for their support and prayers. The tweets and notes have not gone unnoticed. I am very grateful."
She recently confessed that she was scared of the painful surgery and recovery period but wanted to have the mastectomy before the end of the year.