The effect of 3 different doses of chlorampnenicol were studied on rat embryonic and -fetal development. Wistar albino rats received multiple intramuscular injections of 100 mg/kg, 200 mg/kg, and 4OO mg/kg of chloramphenicol for the first 10 days of pregnancy. One group from each dose was seer i f iced on day 13 of gestation and embryos were assessed for growth and development by the aid of the dissecting microscope. The second group of pregnant rats was sacrificed on day 21 of gestation, while the third group was left to continue the pregnancy and dilivered normally. The fetuses of 21-day-old with the newborns were examined externally, which include the entire body surface examination, shape and position of limbs and tail, and inspection of the roof of mouth for possible failure of pa1atal. shelves to fuse ( cleft palate ) . Then, the fetuses and newborns were divided randomly into two groups, the first one was stained with Alizarin-red--s--st.ain for skeletal system assessment, and the second group was prepared for slicing method for detection of soft tissue abnormalities. After assessment of 13—day-old embryos collected from pregnant rats treated with 3 different doses of chloramphenicol, neither growth retardation, nor malforma¬tions were detected.Examination of 21--day-old -fetuses and newborns showed. normal fetal growth and development as manifasted in non¬significant changes in body weight & number of ossification . Entire body examination was normal in all fetuses and newborns and no specific abnormality had been detected with the s1icing method.