Abstract Background: Isotretinoin affects the levels of female hormones and ovaries in patients with severe acne. Objective: This study evaluated the effects of isotretinoin on the ovarian reserve and levels of female hormones in patients with severe acne. Methods: Thirty-two female patients with severe acne were enrolled. All the patients were treated with oral isotretinoin 0.5-2 mg/kg/d. The total cumulative dose for a full course was 120-135 mg/kg. The treatment duration ranged from 5 to 8 months. The serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) levels and antral follicle count (AFC) and ovarian volume (OV) were evaluated before and after treatment. Results: After treatment, the mean FSH, LH, and E2 levels were significantly lower than before treatment. In addition, the mean AFC and OV decreased after treatment, although the difference was not significant. Conclusion: The results of this exploratory study do not demonstrate that oral isotretinoin has an impact in ovarian function. In contrast, isotretinoin affects levels of female hormones in patients with severe acne.