Female Macaca fascicularis monkeys were given daily oral doses of 3.0 and 4.25 mg/kg lead, as lead nitrate, prior to breeding, and exposure was maintained throughout gestation and terminated at parturition. No overt signs of lead toxicity were observed in the maternal monkeys. The offspring were tested at 6 to 18 months of age on a three-choice non-spatial form discrimination paradigm, and at 19 to 26 months of age on a response inhibition task. When compared to controls, the lead-exposed infants showed a deficit in form discrimination performance which continued during the entire period of testing. A deficit in response inhibition performance was also observed in exposed infants when compared to controls. However, the deficit was temporary, as the performance of all groups was similar at the termination of testing.