We prospectively assessed the clinical value of genetic staging of lymph node metastasis in patients with pancreatic adenocarcinoma who underwent curative surgery. K-ras gene mutations were detected in the primary tumors in 18 of 25 patients with pancreatic adenocarcinoma. Among these 18 patients, mutated K-ras gene was also found in at least one lymph node in 13 patients. Of these 13 patients, seven had no evidence of histological nodal involvement and six had histological lymph node metastasis. Although there was no significant difference in overall survival rates between the pathological node-negative and -positive patients, overall survival of the five patients with nodes-negative for the mutated K-ras gene were significantly better than that of the 13 patients with genetically metastasis-positive nodes (p<0.001). Furthermore, overall survival of the six patients with genetically metastasis-positive nodes limited to peripancreatic area was significantly better than that of seven patients with genetical metastasis in lymph nodes beyond the peripancreatic areas (p=0.018). These findings suggest that detection of K-ras gene mutations in lymph nodes may be clinically useful to assess the accurate tumor staging and to stratify the patient with pancreatic adenocarcinoma who are at high or low risk for recurrence after curative surgery.