Purpose: We conducted a comparative survival analysis between patients with resected pancreatic cancer who received adjuvant treatment with either gemcitabine- or 5-fluorouracil-based chemotherapy and chemoradiation regimens. Patients and methods: The Surveillance, Epidemiology and End Results (SEER)-Medicare database was used to identify patients with pancreatic cancer diagnosed from 1998 to 2005 who received curative surgery and adjuvant chemotherapy with either 5-fluorouracil or gemcitabine. These groups were subdivided by treatment with radiotherapy. Patients were followed until death, study end-point or a maximum of 5 years after diagnosis. Results: Three hundred and fifty-nine patients received 5-fluorouracil and 346 received gemcitabine. Compared with chemoradiation with 5-fluorouracil, outcomes for patients who received chemoradiation with gemcitabine did not differ. Patients who received gemcitabine without radiation had increased hazards (poorly differentiated tumours: HR = 1.50, p = 0.01; moderately differentiated tumours, HR = 1.28, p = 0.11). However, outcomes of patients who received 5-fluorouracil without radiation varied with tumour grade. In moderately differentiated tumours, patients had better outcomes with 5-fluorouracil when compared with chemoradiation with 5-fluorouracil (HR = 0.42, p = 0.02). In poorly differentiated tumours, the opposite was true (HR 2.10, p = 0.09). Conclusion: Patients with low-grade resected pancreatic cancer may have better outcomes with 5-fluorouracil-based chemotherapy without radiation when compared with 5-fluorouracil with radiation.