Neonatal treatment with diethylstilbestrol (DES) leads to disruption of spermatogenesis in adult animals after apparently normal testicular development during puberty indicating aberrant androgen action in DES-exposed adult hamsters. The present study determined the effects of exogenous androgens in neonatally DES-exposed hamsters. Exogenous androgens failed to reverse the disruption of spermatogenesis in DES-exposed animals. Neonatal DES exposure caused a significant decrease in seminal vesicle weight, and abnormal histology. While exogenous androgens caused a significant increase in seminal vesicle weight in control animals, they failed to restore the seminal vesicle weight and normal histology in DES-exposed animals. Northern blot and/or RT-PCR analysis revealed that (1) AR, ERα and ERβ mRNA levels were unchanged in DES-exposed animals, and (2) mRNA levels for the AR-responsive genes calreticulin, SEC-23B, and ornithine decarboxylase were significantly decreased in DES-exposed animals. Our results suggest that neonatal DES exposure impairs the action of androgens on target organs in male hamsters.