Treatment of hemorrhoids remains a current problem of modern coloproctology. In the provided research the dependence of results of treatment of hemorrhoids on features of the anatomy of a anal sinus, in particular results of treatment of chronic hemorrhoids in all stages of a current at patients with patholologically the anal sinus changed atypical is revealed it is worse, than in at patients with the typical anatomy of a anal sinus. For identification of pathological features of anal sinus the original way of diagnostics is offered. At a histologic research the pathomorphologic changes of chronic inflammatory process and leading to a metaplasia and a dysplasia of an epithelium were revealed. The treatment undertaken by authors, in the form of excision of a anal sinus at patients allowed to improve results of treatment of chronic hemorrhoids.