Roberts, a 52-year-old breast cancer survivor, had the bone-marrow transplant to treat myelodysplastic syndrome, a rare blood disorder.
"I keep pinching myself and I realize that this is real. This is really happening," said Roberts, who looked beautiful wearing an aqua-colored dress and sporting close-cropped dark hair Wednesday.
"Faith, family and friends have brought me to this moment and I am so full of gratitude," she said. "There's so many people that I want to thank throughout the morning, my doctors and nurses and family and colleagues and people who have sat in this chair and those who have blazed the trail before me. As my mother said, 'We all have something.' Everyone's story has purpose and meaning and value and I share this morning, this day of celebration with everyone."
Roberts' return to the show was announced Feb. 6 after tests showed no signs of abnormalities and she received the all-clear from her doctors, ABC News said. The veteran broadcast journalist then did a series of dry runs at the "GMA" studio in New York, which went well.