Adult volunteers from two neighboring health centers were immunized with measles, mumps, rubella vaccine (MMR, Serum Institute of India Ltd.), either given by traditional injections or by an aerosol delivered to the respiratory tract. Baseline and one month post vaccination samples were taken and simultaneously assayed for all three antigens. Subjects were followed-up for temporally associated events after vaccination. The aerosol route was superior for measles, mumps and rubella when baseline titers were controlled for in multivariate analysis. Frequencies of post-vaccination events did not differ with statistical significance between the groups. Further evaluation of the aerosol route for MMR immunization appears warranted.