Pregnant Sprague-Dawley rats were exposed to radio-frequency radiation at a frequency of 100 MHz and a power density of 25 mW/cm2 for 6 h 40 min daily on gestation days 6--11. The total exposure time was 40 h. The exposure resulted in a specific absorption rate of 0.4 W/kg. This value corresponds to the maximum permissible level for specific absorption rate in the 1982 American National Standards Institute (ANSI) standard for radiofrequency/microwave exposure. The exposure produced no increase in maternal colonic temperature. Irradiated rats did not differ from sham-irradiated rats with respect to the number of implantations per litter, percentage of implantations dead or resorbed, percentage of fetuses malformed. fetal weight, fetal crown-rump length, or fetal sex ratio. The irradiated fetuses had fewer minor skeletal variations than the controls. These results suggest that radiofrequency/microwave radiation is not teratogenic or embryotoxic for rats at the maximum permissible exposure level of the 1982 ANSI standard.