The babies were delivered by Caesarean section Saturday morning, about four weeks before they were due, The Palm Beach (Fla.) Post reported.
Dion's doctors, Ron Ackerman, and Ruel Stoessel, said at a news conference with the singer's manager/husband Rene Angelil that the delivery went according to plans.
The as-of-yet unnamed children weighed 5 pounds, 10 ounces and 5 pounds, 4 ounces, the doctors said.
Dion was admitted to the hospital several days ago in an effort to delay giving birth. She went through at least six rounds of fertility treatment until she announced in May she was expecting twins, the report said.
Angelil, 68, was asked to describe his feelings when he cut the twins' umbilical cords.
"Instant love," Angelil said.