It is generally believed that gastric emptying of solids is regulated by a coordinated motor pattern between the antrum and pylorus. We studied the role of the vagus nerve in mediating postprandial coordination between the antrum and pylorus. Force transducers were implanted on the serosal surface of the body, antrum, pylorus and duodenum in seven dogs. Dogs were given either a solid or a liquid meal and gastroduodenal motility was recorded over 10 hours. Gastric emptying was evaluated with radiopaque markers mixed with a solid meal. Dogs were treated with hexamethonium, L-NAME, or transient vagal nerve blockade by cooling. Postprandial motility pattern showed three distinct phases: early, intermediate, and late. In the late phase, profound pyloric relaxations predominantly synchronized with giant antral contractions, which were defined as postprandial antro-pyloric coordination. Gastric emptying study revealed that the time at which gastric contents entered into the duodenum occurred concomitantly with antro-pyloric coordination. Treatment by vagal blockade or hexamethonium significantly reduced postprandial antral contractions and pyloric relaxations of the late phase. L-NAME changed pyloric motor patterns from relaxation-dominant to contraction-dominant. Solid gastric emptying was significantly attenuated by the treatment with hexamethonium, L-NAME and vagal blockade. Postprandial antro-pyloric coordination was not seen after the feeding of a liquid meal. It is concluded that postprandial antro-pyloric coordination plays an important role to regulate gastric emptying of a solid food. Postprandial antro-pyloric coordination is regulated by the vagus nerve and nitrergic neurons in conscious dogs.