Sex cord-stromal tumors including granulosa cell tumor, thecoma, Sertoli stromal cell tumor and steroid cell tumor are noted for their hormonal activity. However, there are many kinds of ovarian tumors other than sex cord-stromal tumors and tumor-like conditions with endocrine manifestations. Cross-sectional imaging, especially MR, can provide precise features of ovarian tumors and uterine morphological change even in a clinically latent excess of estrogen. In this article, we demonstrate typical imaging findings of ovarian tumors with hormonal activity. We also shortly explain the mechanism of the virilization and hyperestrogenism caused by ovarian tumors and tumor-like conditions.