purpose: To assess the efficacy of acyclovir and intravenous immune globulin (IVIG) for cytomegalovirus (CMV) prophylaxis in high-risk recipients of solid organ transplants. patients and methods: We randomized 21 CMV-seronegative organ transplant recipients with seropositive donors (D+R-) to receive oral acyclovir, 800 mg four times daily, or, in addition to acyclovir, IVIG, 300 mg/kg, every 2 weeks for six doses. Patients were followed closely for the development of CMV infection and disease. results: All but one prophylactically treated patient (95%) developed CMV infection. Fifteen of 21 patients (71%) who received prophylaxis fulfilled criteria for CMV disease. Disease onset was delayed in those who received IVIG, but this did not reach statistical significance. Ganciclovir was used for treatment in 15 of the 21 patients (71%). conclusions: Acyclovir, with or without IVIG, did not prevent primary CMV infection or disease in D+R- solid organ transplant recipients at our institution. Moreover, most patients were treated with ganciclovir despite the use of prophylaxis. Given the ready availability of ganciclovir to treat CMV disease, we recommend a reappraisal of the role of CMV prophylaxis by these means in the solid organ transplant population.