In this retrospective study, the clinical findings of 26 cases borne by alcoholic mothers in Japan are summarized. The information on maternal alcohol drinking and abnormal offspring was gathered by a questionnaire survey. Twenty cases, mostly in institutions for mental retardation, were checked from all areas of Japan. Six children from another group were followed during health examinations of children in a selected area with many heavy drinkers. Growth deficiency was found in half of these cases with an increased rate of low birth weight babies (42% of cases) including small-for-date babies (23% of cases). More than 90% of these cases were in the retarded range of intelligence, 50% of which had IQ scores of 51-75. Gross motor development was also delayed. In all of the 6 follow-up cases, craniofacial anomalies such as hypoplastic nose and philtrum, narrow lip vermilion and short palpebral fissures were observed, although these facial features were mild. An aberrant palmar crease was seen with high frequency. CT of 3 cases did not show constant findings. The mothers were said to have drunk about 0.41 or more of 'sake' or whisky daily (average 110 ml of absolute alcohol) throughout pregnancy. Although typical cases of the fetal alcohol syndrome are less than one-third, this report provides evidence for the presence of mentally retarded children borne by alcoholic mothers in Japan and should alert many medical professionals to this problem.