Between 1983 and 1989 a phase II study was carried out by the EORTC Malignant Melanoma Cooperative Group in which postmenopausal women with advanced melanoma but a good performance status received tamoxifen, 40 mg per day, as a single agent. From 12 centres, 114 patients were registered of whom 107 appeared to be eligible and 102 evaluable. Seven died of progressive disease within 4 weeks, eight others had early progressive disease (of whom seven died within 7 weeks). The response rate was 4.9%, the complete response rate 1%. Without prior chemotherapy three of 58 responded, with prior chemotherapy two of 44. Except for one of 46 patients with lung metastases who experienced a PR of these metastases, all responders were patients with slowly growing small soft tissue metastases. We conclude that, because of the few side effects, tamoxifen can be recommended for (postmenopausal) patients who have only a small number of slowly growing metastases and who are not yet candidates for treatment with toxic drugs.