We investigated the effects of occasional alcohol binges on birth outcomes in a cohort of live singletons born to 709 moderate drinkers recruited from a Seattle, WA, health maintenance organization before their sixth month of pregnancy. We compared infants of women with one or more binges in the month before pregnancy or in the first two trimesters with those whose mothers reported no binges in either period. Mean values of birthweight, length, head circumference, gestational age, intrauterine growth, and Apgar scores did not differ notably between the two groups. The risk of having an adverse neonatal discharge diagnosis initially appeared lower in infants of binging mothers, but this difference vanished after recategorization of the variable and control for confounding. Our results indicate that occasional binges, during a broad window of exposure and among otherwise moderate drinkers, do not adversely affect the birth outcomes examined here.