To investigate the treatment effects of gemcitabine plus S-1 (GS) for metastatic pancreatic cancer in our institution.Data from 41 patients with metastatic pancreatic cancer treated with GS regimen in West China Hospital, Sichuan University were reviewed. The therapeutic efficacy and toxicity were evaluated. The influencing factors of progression-free survival (PFS) and overall survival (OS) were also explored.At the last follow-up, all patients had died. The objective response rate was 22.0% (9/41) and the disease control rate was 65.9% (27/41). The median PFS and OS times were 5.1 (range, 1.5-21) and 10.6 months (range, 1.5-40), respectively. The 0.5-, 1-, and 2-year OS rates were 65.9%, 41.5%, and 9.8%, respectively. In multivariate analysis, body mass index and carbohydrate antigen 19-9 change were the significant influencing factors of PFS, compared to tumor site and chemotherapy cycles for OS. The adverse effects were moderate and tolerable.The effects of GS for metastatic pancreatic cancer in our institution were good. The adverse effects were moderate and tolerable. However, further investigation in future prospective clinical studies is warranted.