Abstract Pregnant rates were fed a control diet, a high saturated fat diet, or a high polyunsaturated diet lacking in vitamin E and zinc, for 6 weeks prior to breeding and continued to consume these diets during pregnancy. Beginning on gestation day 8, rats in each diet group were intubated with 5,3, or 0 g/kg alcohol. Rats in the 0 and 3 g/k group were pair fed to those in their respective 5 g/kg groups. A fourth group received one of the three diets ad lib, and was not intubated. On postnatal day 20, offspring were tested for locomotor activity and head-dipping behavior. Animals prenatally exposed to alcohol were more active and made more head dips than pair-fed controls, but only if their mothers consumed the control diet. Alcohol had an opposite effect on offspring whose mothers consumed the high saturated fat diet, and had no effect on animals consuming the high polyunsaturated/no vitamin E or zinc diet. These preliminary results suggest that dietary fat may modify the behavioral effects of prenatal alcohol exposure. This effect may be the result of the stabilizing effect of saturated fats on cell membranes which increases their resistance to perturbation by alcohol.