Small intestinal submucosa (SIS) is a bioscaffold that has been showing encouraging results with appropriate tissue regeneration in the gastrointestinal tract. We investigated SIS-induced muscle contractility in vivo and in vitro to determine whether the SIS-grafted area would become physiologically functional in the long term. A 1 cm circular, full-thickness defect was created in a rodent stomach and was repaired using SIS. After 1 year, gastric motility in the SIS-grafted area was recorded in awake animals using a telemetric force transducer system. Muscle was obtained from the same area where in vivo motility had been explored. Organ bath technique with electrical field stimulation was applied. Native stomach and grafts were investigated for morphology by histologic and immunohistochemical analyses. Gastric motility during fasting was enhanced by both food intake and a cholinergic agonist. A muscarinic receptor antagonist inhibited postprandial gastric motility. Responses in vivo were equivalent in grafted versus control rats. The in vitro study revealed that the distribution of muscle and nerves in SIS-regenerated tissue would be proportional to that in normal tissue. Smooth muscle, peripheral nerve, and gastric parietal cells were observed in the SIS-regenerated wall. SIS has the potential to promote a physical and physiological regeneration with intrinsic nerve migration.