A study of 149 patients with ovarian cancer compared to 149 age-matched women out of the population is analyzed. There were no statistically significant differences in nearly all extragenital and all gynaecological diseases. No differences were found in menstrual history, history of hormonotherapy, age of menarche and menopause, number od nulliparous women, number of deliveries and abortions, radiation exposure, double primaries, blood groups, family history and consumption of nicotine. The findings in this study showed a difference in two variables: There were more women with hypertension and more never married women among the patients with ovarian cancer. It is not possible to define a group of high risk with these findings. It is suggested that endocrine factors influence the onset of ovarian cancer. Therefore these factors more should be taken into consideration in further epidemiological studies.