Background. The effects of intestinal transplantation on gut motility have not been completely defined. In this study we examine the effects of ileal transplantation on ileal smooth muscle contractility, together with gastroduodenal emptying, intestinal flow, and transit rates in a canine model of short-gut syndrome. Methods. Animals (n = 22) were instrumented with strain gauge transducers, collection cannulae, and infusion catheters to assess motility, intestinal flow and transit rates, and gastroduodenal emptying. Ten animals served to define normal parameters. Six animals underwent a 70% resection of the proximal small intestine to serve as short-gut controls. Six animals underwent removal of a 100-cm segment of the ileum, with cold storage, and autotransplantation the following day combined with a 70% resection of proximal bowel. Results. Transplant animals exhibited delayed gastroduodenal emptying, reduced intestinal flow rates, and postprandial phasic contractions that were similar to short-gut controls. However, transplant animals experienced rapid intestinal transit compared with short-gut controls (4.8 ± 0.4 cm/min vs 2.0 ± 0.3 cm/min; mean ± SEM; P < .05). Conclusions. The transplanted intestine, even with 18 hours of cold storage, exhibits a relatively normal postprandial motor response. However, adaptive responses of the transplanted intestine, such as regulation of intestine transit, may be impaired by neuromuscular injury associated with denervation or ischemia. (Surgery 2001;129:6-14.)