We investigated the effects of gestational exposure to fenproporex, one of the most used anorectic drugs in Brazil, on the behavior of adolescent and adult pups (30 and 60 days of age, respectively). Pregnant Swiss mice were treated daily, by gavage, with 15 mg/kg of fenproporex chloride or water during the whole gestational period. Male pups were submitted to open-field, forced swimming test, tail suspension test and fenproporexinduced stereotyped behavior. The results demonstrated that gestational exposure to fenproporex induces antidepressant-like effect and decreases fenproporexinduced stereotyped behavior in both adolescent and adult pups. Moreover, fenproporex-exposed adolescent pups tended (P–0.06) to be more active than control pups. Our data show, for the first time, that gestational exposure to fenproporex leads to long-lasting behavioral toxicity in male mice characteristic of altered dopaminergic transmission.