Background: Clinical staging of patients with pancreatic cancer is essential to determine if neo-adjuvant treatment, surgery or palliative treatment is required. Patients with early stage disease often receive upfront surgery, where as patients with more advanced disease often receive neo-adjuvant therapy. Therefore the accuracy of clinical staging significantly influences management decisions. This study investigates the correlation between clinical and pathologic staging for patients with stage I pancreatic cancer. Methods: A retrospective review of patients with pancreatic cancer in National Cancer Data Base from 1998-2006 was preformed. The clinical stage of patients with presumed stage I disease was compared to the postoperative pathologic stage. Cox proportional hazard ratio model and regression analysis were used to determine factors associated with mortality and upstaging, respectively. Results: 1697 patients with clinical stage I pancreatic cancer were divided into two groups. Group 1 was comprised of patients who were stage I postoperatively and Group 2 was comprised of patients that were upstaged to either stage II, III or IV postoperatively. There were 704 (41%) in group 1 and 993 (59%) in group 2. Within group 2, 595 (60%) were stage II, 321 (32%) were stage III and 77 (8%) were stage IV. Patients that were upstaged after surgery had an increased risk of mortality (HR 1.414, p < 0.001), whereas patients that received adjuvant chemotherapy had a decreased risk of mortality (HR 0.799, p < 0.001). Compared to Grade 1 tumors, Grade 2 and 3 tumors on biopsy were most likely to be upstaged on final pathology (p < 0.001). Conclusions: Patients with stage I pancreatic cancer are often candidates for upfront surgery, however this study demonstrates that a large number are upstaged on postoperative staging. Recognizing this may lead clinicians to administer neo-adjuvant treatment in a greater number of patients with early stage disease in order to optimize survival.