15 cases of malignant ovarian neoplasms of the period 1948-1974 are being reported. All these women were less than 30 years of age. The youngest patient was 15 years old and 7 were less than 25 years old. These 15 cases represent 2,2% of all ovarian neoplasms with primary surgical treatment at the I. University Clinic of Obstetrics and Gynecology in Vienna in this period. Anamnestic datas, symptomatology and clinical aspects of these cases are reported. Surprisingly high was the rate of 9 cases of primary stage cancer Ia in these young women and girls, which was significant higher than in the total material of the clinic. Therefore it seems intelligible that in spite of the high rate of conservative surgical treatment 9 patients have survived 5 and more years without any symptoms. The possibility of conservative surgical treatment of malignant ovarian neoplasms in young women and teenaged girls of primary stage of cancer Ia is discussed.