Pregnant Sprague-Dawley rats received 25 mg/kg of prochlorperazine, 20 mg/kg of fenfluramine, 75 mg/kg of propoxyphene or 200 mg/kg of diazepam daily between the 7th and 20th days of gestation. Vehicle control groups and a positive control group (vitamin A 40,000 IU/kg/day) were similarly prepared. Observations of reproductive performance were made and the offspring examined in a battery of neurobehavioral tests. Fenfluramine and prochlorperazine produced abnormalities in both the reproductive measures and neurobehavioral testing. Propoxyphene produced developmental delays and other signs of "pure" behavioral teratogenesis in that these effects were not anticipated in any of the observations of reproductive performance. Diazepam appeared to have the mildest effect on all the measurements taken. The test methods used in this study appear to be a reasonable initial approach to the development of neurobehavioral screening procedures which are comprehensive, sensitive, and usable.