401 cases of hormone-producing tumors of the ovary were studied (190 theca-cell, 169--granulose cell, 25--mixed thecagranulosa cell and 17--virilising tumors). Histological diagnosis, clinical stage and end results of their treatment were compared. Theca-granulosa cell tumor is considered to be the most malignant form of these neoplasms. Pure theca-cell tumor proved to be benign in most cases. Of special interest is a high percentage of patients being cured at stage 1 (FIGO classification) of neoplastic process, that stands, in the authors' opinion, in close relationship with comparatively good results obtained in these patients.