A total of 90 patients has been treated with Treosulfan. The minimum follow‐up period was 6 months. Distribution according to age and clinical stages corresponds to what is usually found. The treatment with Treosulfan was given in interrupted causes. The only serious side effect is a depression of the bone‐marrow function. Apart from this, Treosulfan is well tolerated and in most cases the treatment can be carried out in the open ward. It is striking that the general condition of the patients very often was improved considerably. Five patients suffering from disseminated cancer apparently were cured. An excellent effect on ascites was seen since a complete disappearance of ascites was seen in 17 out of 27 patients with serous carcinoma and a transient improvement in six. There was hardly any effect of the treatment of the patients in the terminal stage of the disease. In stage III the average survival time for patients who died of the disease was proportional with the degree of response, viz.: Excellent response: 20.4 months, good response: 15.7 months and no or poor response: 6.0 mon