Purpose: The purpose of the present study was to assess histologically the teratogenic effects of microwave ovens on pregnant and newborn rat brain.Methods: Twenty-seven pregnant Wistar-albino rats were separated into three groups (n=9), a control group (sham-exposed) and two experimental groups. The experimental gravid rats were confined in plexiglas cages placed next to the closed door of a microwave oven. The first group gravids were exposed to the microwave oven daily for 15 minutes whereas the second group gravids were exposed 30 minutes daily during their pregnancies.Results: Striking changes were observed in dams and litters of the second group. Congestive vessels with edema and degenerative neurons were observed in dams of both experimental groups. Chronic inflammatory cell infiltrate and focal necrosis of neural tissue were also observed in the second group dams. Progressive edema with striking congestive vessels were observed in the litters of both experimental groups. Chronic inflammatory cell infiltrate, hemorrhage, degenerative neurons with a reactive glial proliferation, and necrotic neural tissues were noticed only in the second group litters.Conclusion: Pregnant users do not normally stand near to microwave ovens at the same distance as in our experimental condition; therefore, it is difficult to suggest that the microwave oven can cause necrosis in newborn brains every time.