To elucidate the clinical significance of neural invasion in pancreatic carcinoma, a clinicopathological study was performed. Neural invasion is a common feature of pancreatic carcinoma whose clinical significance has not yet been determined. Over a period of > 10 years, 129 of 204 (63%) patients with pancreatic carcinoma underwent resection by extensive radical surgery. A clinicopathological study of those specimens of pancreatic carcinoma was performed, with particular reference to neural invasion. Intrapancreatic neural invasion was observed in 116 of 129 (90%), of which 80 (69%) showed extrapancreatic nerve plexus involvement. A statistically significant (p < 0.001) correlation between the grade of intrapancreatic neural invasion and extrapancreatic nerve plexus invasion was observed. The postoperative survival rate for patients with extrapancreatic nerve plexus involvement was significantly (p < 0.001) lower than that for patients without extrapancreatic nerve plexus involvement. Patients who survived for > 3 years after operation had no extrapancreatic nerve plexus invasion even when portal vein wall invasion was observed.