The effect of in utero cocaine exposure on the postnatal binding of the radiolabeled dopamine (DA) uptake inhibitor [3H]GBR 12935 to the DA uptake complex was examined in male rats. One set of pregnant Sprague-Dawley rats was given subcutaneous (s.c.) injections of cocaine (40 mg/kg) or 0.9% saline from gestational day (GD) 8-21. Another set of animals received bilateral s.c. Silastic implants, each containing 60 mg cocaine base dissolved in polyethylene glycol (PEG) or PEG only, from GD 18-21. The density of [3H]GBR 12935 binding to the DA transporter in striatum and mesencephalon was assessed by quantitative autoradiography on postnatal day (PND) 1, 10, 30, and 60. Both treatment methods resulted in a decrease of [3H]GBR 12935 binding in dorsal lateral striatum of cocaine-exposed offspring on PND 10. There were no significant differences in [3H]GBR 12935 binding between offspring of cocaine and vehicle-treated dams at any other time points examined. Thus, prenatal cocaine exposure by either daily injection from GD 8-21 or continuous infusion from GD 18-21 resulted in a transient decrease in DA transporter binding in the dorsal lateral striatum that was apparent on PND 10.