Treatment with radioactive iodine (RAI) in women with differentiated thyroid cancer is associated with decreased serum concentrations of anti-MĂŒllerian hormone (AMH); however, other markers have not been investigated. Therefore, this study aimed to evaluate the effect of RAI on antral follicle count (AFC) and the serum concentration of inhibin B, follicle-stimulating hormone (FSH), and AMH in women with papillary thyroid cancer (PTC) treated with RAI. We examined 25 women at a median age of 33 years treated with a single dose of RAI. We divided the participants into women over (n = 11) and under 35 years of age (n = 14). Serum concentrations of inhibin B, FSH, AMH, and AFC were assessed at baseline and one year after RAI treatment. We found decreased AFC (p = 0.03), serum levels of AMH (p < 0.01), inhibin B (p = 0.03), but not FSH (p = 0.23), one year after RAI treatment in comparison to baseline in the whole group. When we compared serum levels of AMH in younger vs. older women separately, we observed a significant reduction of this hormoneâs serum level after RAI treatment in both groups (p < 0.01; p = 0.04, respectively). We concluded that RAI treatment significantly impacts the functional ovarian reserve in premenopausal women with PTC.