Ortiz's partner, former adult film actress Jenna Jameson, gave birth to the twins today at a hospital in Newport Beach, California.
Jameson confirmed last September that the two were expecting.
"It has been my dream to have children for an extremely long time, and I truly feel like finally... the time is right and God has blessed me," Jameson wrote on a MySpace blog. "I have never felt more like a woman, or more alive.
"Tito is happier than I have ever seen him, it is so fulfilling to see him so proud. He looked me in the eye today after our doctor's appointment and said, 'I'm the luckiest man on earth... thank you for having my babies.' I cried..."
Ortiz has a son from a prior marriage while the twins are Jameson's first kids.
Ortiz remains a free agent as a fighter and was last seen at Affliction "Day of Reckoning" on Jan. 24 as a color commentator.