Behavioral effects of repeated aluminum administration during prenatal periods were studied in THA rats. Four groups of pregnant rats were administered a daily dose of 0, 90, 180 or 360 mg/kg of aluminum chloride from the 8th day to 20th day of gestation by gavage. No differences were observed between the aluminum treated offspring and controls in terms of body weight. Delays in pivoting, longer latency and more rearings in an open field test were observed in the 360 mg/kg treated group, but no other developmental alterations were found. Urination in the open field test in the 180 mg/kg and 360 mg/kg treated groups was significantly more frequent than in the other two groups of rats. These results suggest that repeated doses of aluminum chloride during the prenatal period affects neuromotor maturation and emotionality in rats.