Normal cohesion of stone and mortar and strength to stretch of mortar in masonry joints depend on many factors that are hardly taken into account in evaluating the normal cohesive strength of stone and mortar. Nevertheless, there are important practical cases where tensile and shearing strength of masonry determine the load carrying capacity of structure. The aim of this work was development of methods for testing the masonry with thin mortar joints and data on normal cohesive strength in such masonry. The results of experimental researches of normal cohesive strength in cement mortar with solid and cavity bricks, porous bricks, silicate bricks and cell-concrete blocks are presented. Experimental dependences for cohesive strength of mortar with referred types of masonry units on compressive strength of cement mortar are obtained.