A search for records for CMV infection following transfusion related to noncardiac and nontransplant operations and trauma disclosed nine instances with CMV seroconversion. One patient had received only a single unit of blood. The most prominent feature was fever with a characteristic spiking plateau pattern, which began approximately three weeks after blood transfusion. Splenomegaly and atypical lymphocytosis were less common. The results of hepatic function tests showed slight abnormalities. Associated splenectomy did not result in a more severe manifestation of the CMV infection. The late postoperative fever in these patients led to an extensive and costly investigation before determination of antibody titers to CMV and confirmation of seroconversion. When faced with the constellation of symptoms, including a delayed (two to three weeks) spiking plateau postoperative fever, abnormal results of hepatic function test and lymphocytosis in patients having received blood transfusion, the clinician must give serious consideration to the possibility of CMV infection.