The reproductive effect of $Telazol^{circledR}$ was studied in pregnant rats. Two different doses (20 or 40 mg/kg/day) were injected on days one of 3, 5 or 8 of pregnancy and 3 consecutive days of 3~5 or 5~7 in pregnant rats. On days 8 or 21, the rats were anesthetized, the cesarean section was performed, the uterus was carefully examined, and the numbers of corpora lutea, implantation sites and viable fetuses, fetal and placental weights and pre-and post-implantation losses in rats were surveyed. Simultaneously the concentrations of sodium and potassium of the plasma, uterine and amniotic fluids were determined. And gestation period in pregnant rats, postnatal offspring survival and body weight gains were evaluated. Administration of $Telazol^{circledR}$ did not exert a bad influence upon body weight gains in pregnant rats. Reproductive indices were normal. The concentrations of sodium and potassium of the plasma, uterine and amniotic fluids in pregnant rats remained unchanged. Gestation period of rats, postnatal offspring survival and body weight gains were normal. It is concluded that $Telazol^{circledR}$ is devoided of significant adverse reproductive effects in pregnant rats.