We report the incidence of cytomegalovirus (CMV) seroconversion, infections and mortality in 169 consecutive thalassemic patients transplanted in Pesaro. We observed a 44% incidence of early seroconversion and a 52% incidence of late seroconversion. No relationship was found between seroconversion and acute or chronic graft-versus-host disease (GVHD) or rejection. The donor status did not influence the incidence of seroconversion, GVHD and rejection. Only three patients died of CMV infection (1.7%); in each case CMV disease was the final cause of death in patients with severe acute GVHD.