The purpose of this study is to determine whether small intestine transplantation could be considered as an alternative treatment in infants and children with short bowel syndrome. The potential nutritional consequence of orthotopic small intestine transplantation was evaluated in a rat model. Young Lewis strain rats (weighing 250 to 275 g) were used. Lewis rats with resection of 90% of the small intestine were studied as short bowel group (group I, n = 5). In the transplant group rats, 90% of the original small intestine was transplanted orthotopically using microvascular techniques (group II, n = 5). During the study period of 8 weeks, group II gained weight at rates equal to that of normal age matched rats (+30% of the preoperative weight), whereas rats with short bowel (group I) lost 10% of their weight. Two weeks following transplantation, serum albumin levels were maintained in the normal range in group II. However, group I rats showed decreased albumin levels. Serum cholesterol levels showed no significant difference between the two groups. Maltose absorption was evaluated as a functional test of small intestinal graft absorption (1.0 mg/g body weight of maltose was orally administered, and serum glucose levels were measured). The glucose level at 45 minutes was significantly blunted in group I in comparison with group II. The data from this study suggested that small intestine transplantation can produce adequate nutritional support to sustain growth and development in this rat model. It would be anticipated that small intestine transplantation in patients with short bowel syndrome would also benefit nutritionally.