Early delayed gastric emptying has been reported as a frequent complication following pylorus preserving pancreatoduodenectomy (PPPD). We investigated the effect of division of the pyloric branch of the vagus nerve and/or transection of the duodenum on gastric emptying using the acetaminophen method in rats to speculate the unknown etiology of early delayed gastric emptying after PPPD. Twenty-four male Wistar rats were divided into the following four groups; Group S, sham operation as controls; Group N, disturbance of neuro-vascular supply to the pylorus; Group D, temporary interference of the duodenal continuity; and Group N+D, with both procedures in Group N and Group D. Gastric emptying was measured using the acetaminophen method at 1, 2, and 4 weeks after operations in each group. No significant difference was observed in Group S at any intervals after the operation. Gastric emptying was prolonged significantly in Group N, Group D and Group N+D compared to Group S until 2 weeks following surgery. Significant delayed gastric emptying was sustained in Group N+D at 4 weeks, although gastric emptying in Group N and Group D was improved by 4 weeks. The results in rodent models suggest that both dissection of the pyloric branch of the vagus and transection of the duodenum might be causative factors of postoperative delayed gastric emptying following PPPD.