Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis with very frequent post-surgical local recurrence. The combination of adjuvant chemotherapy with radiotherapy is under consideration to achieve a prolonged disease-free survival (DFS). To date, few studies have determined protein profiles that are associated with responsiveness to adjuvant chemoradiation. Here, we analyzed the proteomes of primary, surgically resected PDAC tumors subjected to adjuvant chemoradiation and achieving short DFS (median DFS of 6 months, n = 6) or a prolonged DFS (median DFS of 28 months, n = 6) using liquid chromatography tandem mass spectrometry.