A review of mainly histopathologic factors associated with the survival of patients with malignant melanoma was carried out in a retrospective study of 124 Japanese patients treated at the National Cancer Center Hospital between July 1962 and December 1992. There were 60 females and 64 males, and the median follow-up period was 52.7 months (range, 1.1 to 235.3 months). The histologic features included tumor thickness, level of invasion, histologic subtype, ulceration, pigmentation, and cell type. Melanomas thicker than 1.5 mm (P<0.01) and with ulceration (P<0.001) had a significantly worse prognosis. With regard to histologic type, ten-year survival was 65.1% for acral lentiginous melanoma, 50.7% for nodular melanoma, and 47.0% for superficial spreading melanoma (SSM), there being no significant differences among them. We suggest that the prognosis was affected not by histologic type but by the large radial or vertical growth component. With regard to clinical features, the clinicopathological stage, patient age, and year when the disease was diagnosed were reflected in the prognosis (P<0.001). Multifactorial analysis showed that the most significant prognostic variables were histopathologic type (SSM or other), stage (I and II or III and IV), and patient age (<70 or > or = 70 yr).