The parents, Jenni and Dave Ezell, joined staffers from Medical City Children's Hospital for a news conference Thursday, KTVT-TV, Fort Worth, Texas, reported. The operation was performed last weekend.
The conjoined boys, Owen and Emmett, were born July 15. They were joined at the torso, sharing some organs and with a rare condition in which the intestine was outside their bodies, making the surgery even more difficult, doctors say.
Dr. Clare Schwendeman said in similar cases only about 30 percent to 50 percent of separations end up with both twins surviving.
The Ezells were ecstatic about the results.
"It's amazing," Jenni Ezell said, weeping for joy. "It's the most wonderful feeling. I'm just so happy that they're here ... that they're alive and thriving."
The couple learned in March that Jenni was carrying conjoined twins. She said she decided to end the pregnancy after a doctor told her the twins were unlikely to survive but changed her mind after talking to doctors at the Dallas hospital.
"The whole pregnancy was very frightening," she said.
Schwendeman and other doctors are unsure how soon the boys will be able to leave the hospital.