For the first time, we performed an epidemiological study of SSc in Japan to study the factors influencing prognosis, survival rate and cause of death of Japanese SSc patients and to compare our data with those from foreign countries. Prognosis of 496 Japanese patients with progressive systemic sclerosis (SSc) was analyzed based on clinical data described in case cards provided by the members of the Scleroderma Research Committee of the Japanese Ministry of Health and Welfare. The essential observation period was from 5 to 20 years, at ending in 1994. Ninety patients died (males 11, females 79). The age of onset of the deceased patients was significantly higher than that of surviving patients (deceased, 45.6 yrs, surviving 41.3 yrs). Statistically significant factors for a poor prognosis were as follows: Barnett type III > type II > type I, positive for anti-Scl-70 antibody, negative for anti-centromere antibody. The survival rate at 5 years after the onset of the disease was 0.937, followed by 0.82 at 10 years, 0.567 at 20 years and 0.40 at 30 years after the onset. Sex was not a predictor for prognosis, although male patients died at an earlier stage of the disease. The most common causes of death were heart failure, pulmonary insufficiency, lung fibrosis, and renal failure. Twenty-four patients had cancer of which 13 were lung cancers. The current status of the survival rate and prognostic factors of 496 Japanese SSc patients is summarized. In future, more well-controlled studies using the same criteria should be performed for the better understanding and management of SSc.