Forty-one patients with advanced ovarian cancer (FIGO stage III or IV) who had relapsed following conventional treatment were treated with long acting depot preparation of D-Trp-6-LH-RH once a month. There were no exclusion criteria and patients of any age or performance status were eligible. Thirty patients continued to progress following therapy. Twenty-six patients died within the first 16 weeks from onset of therapy. Five patients remained stable (SD) on D-Trp-6-LH-RH with no change in tumor size. Six patients had evidence of clinical and/or radiological partial remission (PR) where the tumor size decreased by more than 50%. The remissions in the responding patients were maintained for a mean duration of 10 months (range 6-18 months). Thus 11 patients (6 PR + 5 SD) have had remission or stabilization of disease which has been clinically worthwhile. Clinical benefit of therapy with microcapsules of slow-release D-Trp-6-LH-RH in about 26% of patients is highly encouraging. Treatment with D-Trp-6-LH-RH offers an important non-toxic alternative in patients who do not tolerate chemotherapy or who have progressive disease following chemotherapy.