The present study had the objective of analyzing morphometrically the occupied area by the ovarian follicles in ovaries of pinealectomized female rats. To do so, 24 albino female rats (Rattus norvegicus albinus) were used, which were equally divided in the following groups: Group I ­ sham-pinealectomized rats and kept in the light/dark cycle (12/12 hours), for three months; Group II ­ pinealectomized rats and kept in the light/dark cycle (12/12 hours), for three months; Group III ­ pinealectomized rats and kept in the absence of light for three months; Group IV ­ sham-pinealectomized rats and kept in the absence of rats for three months. The results showed that the groups I and IV presented, respectively, average of 19,00 and 25,00, while groups II and III presented the highest average, 28,25 and 27,25, respectively, indicating, this way, a bigger occupied area by the follicles. It was observed a small amount of corpus luteum in the pinealectomized groups. So, we conclude that the pinealectomy can exert, in a certain period of time, some influence in the gonadal function, what might induce the formation of an anovulatory clinical patology and consequently the development of policystic ovaries