Cancer of the ovary represents the major cause of death due to malignancy in gynaecology. The gravity lies in its method of growth and the difficulties of early diagnosis, that are inherent for cancer localised here. The most frequent histological type is cystadenocarcinoma. The spread of ovarian cancer is above all intra-peritoneal but may also be to retroperitoneal nodes. Surgery must be the first therapeutic step because it enables a firm diagnosis and staging. The most essential prognostic factor is the amount of residual tumour post-operatively. The excision must therefore be as complete as possible, to allow maximum benefit from post-operative chemotherapy. The indication for radiotherapy are limited. The dogma of a systematic second look laparotomy is being put into question. In spite of the undoubtable therapeutic progress, survival of advanced ovarian cancer (the most frequent form) remains very low.