The present study was designed to elucidate the possibilities for the application of angled endoscopes in the sanation of those compartments of the middle ear which are difficult to access for visual control with the use of a microscope, such as the retrotympanic structures (e.g. tympanic and facial retraction pockets), anterior epitympanum, etc. To this effect, we have undertaken the analysis of the results of surgical interventions on the children presenting with chronic suppurative otitis media and concomitant cholesteatoma. A total of 59 primary operations and 35 secondary ones were performed to treat recurrent cholesteatoma. In 41 cases, the surgical intervention was carried out without the endoscopic assistance whereas in the remaining 53 ones the microscopic observation of the difficult-to-access compartments of the middle ear were supplemented by the application of an angled endoscope. Whenever residual portions of cholesteatoma were identified, they were removed under the endoscopic control. The algorithm for the endoscopic assistance during such operations has been proposed, its advantages and limitations are considered. It is concluded that the combination of microscopic and endoscopic techniques for the examination of and operation on the middle ear creates the conditions for the more reliable (in comparison with the traditional otomicroscopic methods) removal of the residual cholesteatoma tissues and thereby allows to reduces the risk of development of residual cholesteatoma from 25% to 13.5%. The results of the present study have demonstrated the necessity of development of a universal approach to the identification of the clinically significant manifestations of chronic suppurative otitis media and cholesteatoma.