The status of vaccination against cytomegalovirus (CMV) at the end of 1988 was as follows: (1) The Towne live attenuated vaccine produces humoral and cellular immune responses without viral excretion or demonstrated latency. (2) The Towne vaccine partially protects seronegative renal transplant recipients from severe CMV disease but does not prevent them from getting infected. (3) In healthy subjects the live vaccine is also protective, but protection is related to challenge dose. Vaccine-derived immunity is equivalent to natural immunity for prevention of disease but at higher challenge doses is less protective for prevention of infection. (4) The viral envelope contains proteins that can stimulate humoral and cellular immune responses, although it is not yet clear whether the responses are as protective as those following infection. (5) One glycoprotein of the envelope, the 55-58K protein, can stimulate the same responses. If large amounts of this protein can be produced by molecular biologic techniques, this protein might be used as a subunit vaccine. (6) Target groups for vaccination would include seronegative healthy women and seronegative or seropositive recipients of solid organ transplants.