Milligan-Morgan hemorrhoidectomy using radiofrequency dissection (Ligasure) has been proposed instead of conventional diathermy in view of its potential benefits in terms of postoperative anal pain and better hemostatic control, but the medical literature is still controversial. This multicenter, randomized, controlled trial was designed to compare the outcomes between Ligasure and conventional diathermy hemorrhoidectomy in the Milligan-Morgan procedures in a sufficient number of patients. METHODS: Patients with Grades III and IV hemorrhoids were randomized to two groups: Ligasure hemorrhoidectomy and conventional diathermy. Postoperative anal pain was measured by the Visual Analog Scale (VAS) and the analgesia required. Postoperative complications, wound healing, and return to working activities also were evaluated as secondary outcomes. RESULTS: A total of 273 patients, well matched for age, gender, working activity and grade of hemorrhoids, were randomized to two groups: Ligasure 146, and diathermy 127. The severity of postoperative anal pain was significantly less in the Ligasure group when measured at least 12 hours after defecation (P