Fifty-five evaluable patients with disseminated malignant melanoma were treated with the combination of dacarbazine (DTIC) 400 mg i.v. on days 1 to 3 and lomustine (CCNU) 50 to 80 mg m-2 orally on day 1 with intervals of 6 weeks as the first line chemotherapy. Three (5%) patients had complete and 6 (11%) partial response, and 7 (13%) patients had stable disease at least for 3 months. The patients with an objective response (n = 9) survived longer than the rest of the patients if the length of survival was calculated from the start of chemotherapy (P = 0.0006). However, the responding patients also had longer time interval from the diagnosis to the detection of distant metastases (P = 0.05), and survival time from disease progression following DTIC and CCNU therapy (P = 0.005). These findings suggest that patients with an objective response to DTIC-CCNU therapy have melanoma with a slow progression rate, and prolonged survival in such patients may in part result from the less aggressive biological nature of their tumours.