Aim of investigation. To estimate efficacy of Doppler-controlled dearterialization of internal hemorrhoids with mucopexy by instrumental diagnostic tests. Material and methods. Randomized, prospective trial included 240 patients with hemorrhoids of the 3-4th stage. Patients of the first group (n=120) underwent Doppler-controlled hemorrhoid artery ligation with mucopexy, the second group patients (n=120) - hemorrhoidectomy by harmonic scalpel. All patients underwent instrumental tests (colonoscopy, ultrasonography by transrectal ultrasound probe, anorectal manometry) in pre- and postoperative period. Results. In both groups control instrumental assessment was carried out in 45 days after surgery. At anorectal manometry decrease of mean resting anal canal pressure after dearterialization with mucopexy was detected, and became comparative to post-hemorrhoidectomy level. Control colonoscopy at first group patients revealed preserved integrity of anoderma and mucosa of low ampullary region of the rectum with complete elimination of hemorrhoid tissue. At control ultra sonography by transrectal ultrasound probe after dearterialization with mucopexy neither cavernous tissue nor blood vessels feeding hemorrhoids were visualized, that was comparable to post-hemorrhoidectomy data. Conclusion. The Doppler-controlled hemorrhoid artery ligation with mucopexy is pathogenically justified surgical procedure with comparable efficacy to hemorrhoidectomy, that is confirmed by instrumental diagnostic tests. Keywords: hemorrhoids, Doppler-controlled dearterialization with mucopexy, hemorrhoidectomy, ultrasonography by transrectal ultrasound probe, anorectal manometry.