Ethanol was administered to pregnant cynomolgus monkeys (Macaca fascicularis) from day 20 to 150 of gestation. The ethanol was delivered by intragastric intubation twice a day at 8 AM and 5 PM. Dosage was begun at a relatively low level, 2 g/kg/day and increased gradually to attain a final dosage of 4 or 5 g/kg/day. The offspring were allowed to be delivered naturally and remained with their mother until 23 days of age when they were sacrificed. Maternal blood ethanol and acetaldehyde levels were monitored at weekly intervals throughout pregnancy. Pregnancy wastage in the form of abortions and stillbirths was increased by ethanol treatment especially at the high dose. Birthweight was significantly lowered in offspring of mothers receiving 5 g/kg/day of ethanol. However, no structural malformations or facial changes suggestive of those seen in the human fetal alcohol syndrome were found in any of the offspring. We conclude that the conditions of our study did not produce a satisfactory model of human fetal alcohol syndrome.