We performed a retrospective survey at 15 hospitals in Niigata Prefecture to assess the effectiveness of gemcitabine in patients with stage IV pancreatic cancer and to analyze prognostic factors impacting survival in patients with stage IVb. The subjects were 244 unresectable or metastatic pancreatic cancer patients(IVa 68, IVb 176)who were treated with gemcitabine as first-line therapy. The overall response rate was 6.1% and the median survival time(MST)was 194 days. The MST of stage IVa(312 days)was double that of stage IVb(167 days). Prognostic factors for survival of patients with stage IVb were analyzed(performance status, response rate, liver metastasis, peritonitis carcinomatosa, paraaortic lymph node metastasis)with the Cox proportional hazards model. Performance status, response rate, and liver metastasis were significant factors influencing survival. When we compare an effect of other chemotherapy with GEM, we should treat stage IVa and stage IVb separately, and subdivision is necessary for stage IVb.