Background: Stratification of pancreatic cancer patients based on early recurrence and prognosis is essential for selecting optimal therapeutic strategies. The aim of this study was to investigate whether serum carbohydrate antigen (CA) 19-9 levels can be better used to predict early recurrence and prognosis. Methods: Patients whose CA 19-9 levels obtained in association with total bilirubin .2.0 mg/dL and whose CA 19-9 levels ,5.0 U/mL were excluded to avoid the influence of obstructive jaundice and Lewis phenotype Le aÀbÀ , respectively. A total of 125 pancreatic cancer patients who underwent surgical resection were enrolled. Results: Larger tumor size, higher serum CA 19-9 level, higher C-reactive protein (CRP) level, more advanced T status, and lymph node metastasis were significantly associated with recurrence within 1 year after surgery (early recurrence). The rate of early recurrence in patients with CA 19-9 levels .100 U/mL (76.9%) was significantly higher than that of patients with CA 19-9 levels 100 U/mL (27.9%). We performed combination analysis of 2 additional risk factors, CRP level (cutoff: 1.0 mg/dL) and tumor size (cutoff: 3.0 cm), with serum CA 19-9 level (cutoff: 100 U/mL). Patients were divided into 3 groups according to their number of risk factors. Rates of early recurrence in patients with 0, 1, and 2 or 3 risk factors were 22.0%, 45.2%, and 91.7%, respectively. Moreover, overall survival was significantly different in each group. Conclusion: Serum CA 19-9 level, in addition to CRP level and tumor size, improve patient stratification in early recurrence as well as prognosis.