PURPOSE: We aimed to identify the need for an adjunctive internal sphincterotomy based on an evaluation of the changes in the symptoms and manometric results after a hemorrhoidectomy for hemorrhoids with difficulty in evacuation. METHODS: Twenty-five (25) patients who had hemorrhoids with difficulty in evacuation and 13 patients who had hemorrhoids without difficulty in evacuation were prospectively evaluated. Patients were interviewed about symptoms and underwent anorectal manometry before and 2 months after surgery. Difficulty in evacuation is defined as the difficulty that a patient has when trying to evacuate the rectum. RESULTS: There were significant differences in the sex ratio, the frequency of bowel movements, and the duration of bowel movements between the two groups (P<0.05). In cases with difficulty in evacuation, the frequency of bowel movements was significantly higher postoperatively and the duration of bowel movements was significantly shorter (P<0.05). The symptom of difficulty in evacuation disappeared in 21 of the as patients experiencing such a symptom, and was improved in the remaining of patients (P<0.05). Following the hemorrhoidectomy for the patients with difficulty in evacuation in the mean and the maximum resting pressure, and the maximum squeeze pressure decreased significantly (P<0.05). CONCLUSIONS: An adjunctive internal sphincterotomy was not necessary for patients who had hemorrhoids with difficulty in evacuation because following the hemorrhoidectomy, the resting pressure was significantly decreased, and the difficulty in evacuation had nearly subsided.