&NA;Fecal stasis in an ileal reservoir may lead to overgrowth of bacteria and changes in mucosal morphology that are of future concern. Moreover, improper evacuation may lead to increased stool frequency and reduced continence. The aims of this study were: 1) to compare the functional results of two types of ileal reservoirs constructed with an ileoanal anastomosis, 2) to compare their emptying to a normal rectum as assessed by a radionuclide enema, and 3) to correlate functional results with emptying. The reservoirs were made of two (J) or three (S) limbs of terminal ileum. Thirty‐three patients (16 with J‐pouch and 17 with S‐pouch) and ten healthy controls were included in the study. There was no difference in the mean age of patients or interval following diverting ileostomy closure. Functional results were obtained by written questionnaire assessing stool frequency, anal soiling, use of medication, need for intubation, and episodes of pouchitis. Emptying was measured with instillation per anus of a semisolid medium labeled with 1.0 mCi of Tc‐99. Ileal pouch counts were measured using a scintillation camera and computer before and after spontaneous evacuation. The emptying was defined as the difference in counts divided by preevacuation counts. The functional results were similar in the two groups. Nocturnal soiling occurred more frequently in the S‐pouch group. Pouchitis occurred in seven patients. Emptying of the two types of reservoir was similar (J: 72±4%, S: 67±5%), but it was less efficient than a normal rectum (90±3%,P<0.004). No correlation was established between age, sex, number of stools, pouchitis, and the efficacy of emptying.The clinical outcome of two patients who emptied less than 30%, however, was greatly improved by intermittent intubation. In conclusion, a semisolid radionuclide enema can be useful to identify patients who would benefit from intubation. No persistent defect in emptying was detected in patients with pouchitis.