Objectives: Total colectomy with ileorectal anastomosis is the gold standard surgical procedure for patients with slow transit constipation (STC). This operation's outcomes are highly variable; however, predictors of postoperative outcomes after surgical treatment of intractable STC remain unclear. This study aimed to clarify the usefulness of preoperative evaluation for intractable STC by computed tomography (CT) in predicting postoperative outcomes. Methods: From January 2011 to December 2018, 22 patients with intractable STC underwent laparoscopic total colectomy with ileorectal anastomosis at the Kashiwa Hospital, Jikei University. They were divided into two groups, eighteen patients in the colonic inertia type (CI) group, and four patients in the spastic constipation type (SC) group, by preoperative CT according to specific criteria. Results: There were no significant differences in the mean age, gender, mean operation time, or mean intraoperative blood loss. The SC group's postoperative hospital stay was significantly longer than that of the CI group. Postoperative gastric outlet obstruction occurred in two patients (11%) who underwent distal partial gastrectomy with R-Y reconstruction after the surgery in the CI group but no patients in the SC group. Postoperative pelvic outlet obstruction occurred in all four patients who underwent ileostomy within a year after surgery in the SC group but no patients in the CI group. Conclusions: The outcomes of total colectomy in the treatment of intractable STC are highly variable. Preoperative evaluation for intractable STC by CT seems to be a useful predictor of postoperative outcomes.