Concern has recently been renewed about detrimental effects of maternal alcoholism on human prenatal development. In light of current interest in maternal alcoholism, data are presented on the effects of ethyl alcohol administration to pregnant mice. Alcohol treatment consisted of intraperitoneal injection of 0.030 ml. per gram of body weight of a 25 per cent (v/v) solution of 95 per cent ethyl alcohol in saline. Following alcohol treatment on both of gestation days 8 and 9 or days 10 and 11 the frequency of fetal death was substantially elevated compared to saline-treated controls. Alcohol treatment on one of gestation days 7, 8, 9, 10, 11, or 12 resulted in significantly increased fetal death following alcohol treatment on day 8. The incidence of congenital anomalies was significantly increased following alcohol treatment only on gestation days 8, 9, or 10. The most frequently observed abnormalities were coloboma of the iris and ectrodactyly affecting the forepaws.