The reality TV star shared on her website that the baby's name is Saint West.
Saint weighed 8 lbs., 1 oz., when he was born on Dec. 5, a few weeks before his due date.
"Kim Kardashian West and Kanye West welcomed the arrival of their son this morning," the couple announced on Saturday. "Mother and son are doing well."
"I don't have names, which is so crazy," she said last month. "We just started talking about it and that was the last thing for us last time. So I feel confident obviously that we'll figure it out."