The authors report their experience of internal, medial posterior with anoplasty and left lateral, sphincterotomy during haemorrhoidectomy according to Milligan and Morgan. Internal sphincterotomy represents a valid complement to haemorrhoidectomy assuring a better postoperative period: it removes the pain by hypertone of the internal sphincter and avoids the stenosis. The indications for both sphincterotomy techniques are suggested by anatomo-clinical characteristics of the lesion and by combined pathologies.