Ten-month-old twins who were separated were being closely monitored by doctors for any signs of infection from the long and complicated surgery.
Regina and Renata Salinas Fierros remained on ventilators and were listed in serious but stable condition Friday morning as they lay in side-by-side beds in intensive care at Childrens Hospital Los Angeles.
"They're medically sedated. They're resting comfortably," hospital spokesman Steve Rutledge said.
The first 48 hours after surgery will be critical for the twins, doctors said.
"To see the girls today beginning to wake up and move and respond is great excitement for us all," lead surgeon Dr. James Stein said Thursday.
Doctors said the girls wiggled their legs after they were taken from the operating room earlier Thursday. Renata, whose operation ended after her sister's, was the sleepier of the pair. Regina moved an arm, doctors said.
The operation began at 6 a.m. Wednesday, and the reconstructive surgery ended about 4 a.m. Thursday, two hours earlier than doctors had anticipated.
The girls were born facing each other and joined from the lower chest to the pelvis. Doctors made an incision at the breastbone and then divided the internal organs. The twins shared a large intestine and doctors decided to give the organ to Renata. Regina might require a colostomy later in life, doctors said.
Both will require physical therapy and possible additional surgeries, doctors said. They said the girls should live normal lives.
The girls' parents, who came from Mexico, said they have not decided whether they will return to their country.
Sonia Fierros, 23, said there's a lot she looks forward to: "To see our daughters run, go to a normal school, to prepare themselves for life, to enjoy everything that life has to offer."