In this retrospective review of 164 consecutive patients with malignant ascites it has been shown that ovarian ascites accounts for 28% of the total and is associated with a significantly improved survival compared with other groups (P<0.001). Non-ovarian ascites is associated with a very poor prognosis and many patients in this group are unsuitable for aggressive treatment. In 49% of patients, ascites will be the presenting feature requiring further investigation to ascertain the primary tumour. Thorough investigation of female patients should be performed in order to identify all patients with an ovarian primary so that appropriate chemotherapy can be given. However, thorough investigation in male patients is not justifiable.