The former CSI: Crime Scene Investigation star and his wife Gina Cirone used a surrogate for the birth.
The twins - a boy and a girl - were born prematurely last month (05Jul11).
Petersen tells People.com, "The babies are doing great and are improving every day and we can't wait for them to come home."
The actor and Cirone wed in 2003. Petersen is also a grandfather to his 36-year-old daughter Maite's two children.