Sažetak Due to their morphological characteristics molars require a special technique of work. Amputation treatment does not satisfy modern endodontic demands. The author points at the need for exact intracanal instrumentation and particularly at the difficulties in instrumentation of mesio-buccal canals of the upper and lower molars. A quite frequent occurrence of pulp concretions in molars can partly or totally disable the instrumentation of root canals as well as the whole endodontic treatment. An early detection of pulpolithes in molars by X-rays w ill enable their easy removal. In over 90% of 195 clinical cases with treated molars in a five year period the complete instrumentation and filling of root canals were carried out. Although in 67% of pa-tients with treated molars aged over 41 a partial sclerosis of root canals could have been expected, the complete instrumentation of root canals was successfully performed. The author presents four cases selected from a large number of clinical cases. Apparent successful treatments of molars show that they require an exact endodontic treatment.