Cytomegalovirus (CMV) is the leading cause of infectious complications after organ transplantation. We report the case of a 55-year-old renal transplant recipient who presented with CMV infection 2 months after transplantation. During oral ganciclovir treatment (5 weeks after interruption of intravenous ganciclovir), he experienced a sharp pain in the right shoulder. Examination was normal, but CMV antigenemia remained positive with 30 cells/300,000. He underwent a shoulder puncture, which confirmed the presence of CMV in the articular fluid after evaluation by polymerase chain reaction gene amplification. The patient recovered from his arthritis of the shoulder, and antigenemia became negative after 3 weeks of parenteral ganciclovir. We describe a CMV arthritis that occurred despite a curative treatment for CMV disease, and comment on the pathogenesis of this infection, the pharmalogical failure, and dosing or treatment duration.