Malignant ovarian tumours in 199 patients were studied for their lymphogenic expansion, depending on histological tumour types and on criteria for classification by stage. The condition of the tumour capsule was found to be the most important indicator to incipient lymphogenic dissemination, with an exception being recordable only from dysgerminomas. These insights together with additional considerations have formed a background against which recommendations are made for indications for lymphography of patients with malignant ovarian tumours.