The "Good Morning America" co-anchor was seen from her New York hospital bed in the video.
"Thoughts are so powerful. You've got to change the way you think in order to change the way you feel," she said. "And let me just say this lastly, I feel the love and I thank you for it. Thank you."
Roberts' transplant comes after 11 days spent in the hospital and eight days of chemotherapy to prepare her for the procedure. Her donor is her older sister, Sally-Ann Roberts.
In June, Roberts revealed that she had myelodysplastic syndrome, or MDS, from complications from the breast cancer treatment she underwent five years ago.
It is not yet known when Roberts will return to the morning show, but she said she will return "as soon as I can."
ABC News and The Associated Press contributed to this report.