Macromolecules proteins constitute in the range of 80% of the cell dry mass and actively participate in most cellular processes. Multiple signaling pathways stimulate the protein synthesis. Amount of protein in the cell is increased by protein synthesis on ribosomes or by synthesis of new ribosomes that increase protein synthesis capacity. Molecular processes that regulate the synthesis of new proteins and their degradation are key to the normal functioning of all mammalian cells. In responding to physiological and pathological conditions in the cell they are appear the changes in total protein synthesis. There are numerous signaling pathways in the body that encourage the synthesis of ribosomes or proteins, and are key for the normal functioning of all cells in the body. However, in the cell, protein homeostasis is impaired by intracellular or extracellular factors. Therefore, it is extremely important to determine the intensity of protein synthesis in the cell to get a information about cell function. In this work was tested a method for monitoring the protein synthesis intensity which is based on the measurement of the amount of O-propargyl puromycin, the puromycin analogue, in the newly synthesized proteins by immunofluorescence analysis. The protein synthesis intensity was determined in A549 cells and in mouse embryonic fibroblast cells at different times after the addition of O-propargyl-puromycin. The results showed that the optimal incubation time for A549 cells and mouse embryonic fibroblast cells with O-propargyl puromycin is 60 minutes and that the use of O-propargyl puromycin is an effective method for determining protein synthesis capacity in A549 cells and mouse embryonic fibroblasts cells.