Introduction There are few reports regarding risk of COVID-19-associated complications in bone marrow recipients. We report a patient who had graft-versus-host disease triggered by COVID-19. Results The patient was a 17-year-old boy who underwent HSCT from matched sibling donor for CML. He had complete donor chimerism at day +30. Cyclosporine was tapered and stopped at day +65. Until day +93, he had no complaints. The patient started to suffer from cutaneus and gastro-intestinal grade III GVHD after the diagnossis of CIVID-19. Discussion In the absence of any other condition to explain this clinical picture and the good response to GVHD treatment indicate that the triggering factor in the development of GVHD may be COVID-19 in the era of TLR, which plays a common role in the pathogenesis of both GVHD and COVID-19.