All organisms are exposed to chemical agents during their lifetime. One of these agents is a pesticide that is used as fly killer. In this study we investigated the effects of permethrin on rat ovaries using light and electron microscopy. We used 24 Wistar albino female rats and divided them into 3 groups. Dosages 20 and 40 mg/kg/day permethrin were administered by gavage for 14 days. Normal saline was given to control rats. After treatment, ovarian tissues were collected and prepared for light and electron microscopy evaluation. Negative effects of permethrin were detected on follicular and corpus luteum cell morphology in a dose dependent manner when compared with the control group. Picnotic cellular appearance and condensed chromatin were detected as evidence of apoptotic cell death. Furthermore, degenerative changes were seen in the ultrastructure of mitochondria and endoplasmic reticulum. Thus, these findings suggested that permethrin caused degenerative effects on ovarian morphology in a dose dependent manner. (C) 2015 Elsevier GmbH. All rights reserved.