Background: Current clinical guidelines recommended adjuvant chemotherapy for all resectable pancreatic cancer after operation. The treatment choices included Gemcitabine monotherapy, S1 monotherapy, Gemcitabine+Capecitabine or mFOLFIRINOX. However, the role of Gemcitabine+S1 combination as adjuvant chemotherapy was not clear. We aimed to investigate the benefit of adjuvant chemotherapy with Gemcitabine+S1 in resectable pancreatic cancer. Methods: We retrospectively reviewed the medical records of patients with resectable pancreatic cancer who underwent curative surgery and adjuvant treatments at Taichung Veterans General Hospital (Taichung, Taiwan) between January 2014 and July 2021. The clinical characteristics and outcomes were analyzed. Results: A total of 102 patients received operation were analyzed. 73 patients received adjuvant chemotherapy, including 35 patients received Gemcitabine+S1 combination. Median follow-up period was 22.7 months. The disease-free survival (DFS) and overall survival (OS) among patients received Gemcitabine+S1 combination were 15.5 months and 32.8 months, respectively. Compared with Gemcitabine monotherapy, there was a trend of superior DFS (10.5 months in Gemcitabine monotherapy, p = 0.071), but no OS benefits (23.1 months, p = 0.441) with Gemcitabine+S1 combination. When focusing on more advanced disease status (stage II and III), the Gemcitabine+S1 combination had statistically significant longer DFS (14.7 months vs. 8.6 months; p = 0.015) and OS (30.3 months vs. 21.7 months; p = 0.036), compared with Gemcitabine monotherapy. Conclusions: In our retrospective study, Gemcitabine+S1 combination could be another choice for resectable pancreatic cancer, especially in more advanced disease (stage II and III). Further result from prospective study (JSAP-04) is pending.