Although cytomegalovirus (CMV) is rarely cultured from peripheral-blood leukocytes of immunocompetent patients, it may be cultured from up to 60% of renal transplant recipients, 1 to 4 months after transplantation. During this same period, renal transplant recipients are often referred for psychiatric evaluation. Since CMV may infect the central nervous system, the relationship between isolation of CMV from peripheral-blood leukocytes (viremia) and psychiatric evaluation was investigated in 80 renal allograft recipients at the Massachusetts General Hospital. Five of 16 (31%) patients with viremia and 7 of 64 (11%) patients without viremia required psychiatric consultation (P = 0.04, two-tailed Fisher exact test). CMV viremia may be an important but treatable contributor to psychiatric symptoms in the transplant recipient.