A teratogenic study was carried out on New zealand White rabbits in order to examine the teratogenic potentiality of the recombinant human interferon-${alpha}$A(rHuIFN-${alpha}A$), an available therapeutic agent. The rHuIFN-${alpha}A$ was intravenously administered at dose sevels of $1{ imes}10^5$, $4{ imes}10^5$ and $1.2{ imes}10^6$ I.U/kg/day for a period of13 days from day 6 to day 18 of gestation. Two-thirds of the pregnant females in each group were sacrificed on day 29 of gestation and their fetuses were examined. The remaining dams were allowed to litter naturally, and the postnatal develpment of the offsprings was observed. The administration of rHuIFN-${alpha}A$ during a period of organogenesis produced no embryotoxic and teratogenic effects.