THE LAST major epidemic of rubella occurred in the United States in 19641 with resultant large-scale toll in infant deformity and fetal death. The next significant occurrence of the disease is expected in 1970 or 1971. High priority is being given to development of a rubella vaccine which will help to forestall this event. To be acceptable, a rubella vaccine should: (1) cause little, if any, clinical reaction; (2) induce high level antibody which is persistent; (3) be protective against the natural disease; (4) be noncontagious to susceptible contacts, especially to pregnant women, and (5) be prepared using a safe and acceptable cell culture system. Rubella virus vaccines developed in our laboratories have been viewed from these standpoints. Substantial progress has been made to date and the scientific data considered essential to rendering a judgment of safety and efficacy have been accumulated. The present status of development in our