Shannon Tavarez received an umbilical-cord blood transplant Tuesday at Cohen Children's Medical Center in New Hyde Park, on New York's Long Island.
Dr. Joel Brochstein said in a statement Wednesday that there were no complications and that Shannon is in excellent condition.
He says it will take at least two weeks to tell whether the procedure was successful.
The actress was forced to quit the show in April. Cast members held bone marrow donor registration drives, but a perfect match was not found.