This study demonstrates the serologic response as measured by the HAl test and the side reactions of the HPV-77 DK-12 live rubella vaccine in a small group of adult females. One hundred percent seroconversion was obtained using this vaccine. The mean titers obtained in two separate time periods post-vaccination are higher than those reported for several other rubella virus vaccines. A 66% occurrence of joint symptomatology was recorded post-vaccination with a mean duration of 11.6 days; 24% of women who received placebo reported joint complaints which had a mean duration of 2.0 days. The difference between these two rates is somewhat greater than that reported for other HPV-77 strain vaccines and the average duration of these complaints is longer. The other symptoms reported postvaccination seemed insignificant when comparing both the placebo and the vaccine group. One woman became pregnant three months after vaccination and was subsequently therapeutically aborted. At the time of therapeutic abortion, attempts were unsuccessful to recover rubella virus from the products of conception and cervical swabs