Pregnant Sprague-Dawley rats were exposed to either 3500 or 7000 mg/m3 p-xylene from days 7-16 of gestation. Dams were allowed to give birth, and litters counted, weighed, and observed for external malformations on postnatal days (PD) 1 and 3. Litters were normalized to 8 pups (4 males and 4 females +1) on PD4. On PD21 animals were weaned and littermates housed by sex. Body weights were recorded weekly until weaning and once every two weeks thereafter. Central nervous system development was evaluated by acoustic startle response on PD13, 17, 21, and 63 as well as figure eight maze activity on PD22 and 65. The data indicate that p-xylene as administered in the study does not appear to be a selective developmental toxicant in the rat. (Copyright (c) Elsevier Science Publishers B.V. (Biomedical Division).)