Cardiac muscle tissue (myocardium) is a specific muscle tissue in the body, providing the contractile function of the heart. This tissue differs from other muscle tissues in a number of morphological and functional ways. This article analyzes the microscopic structure of cardiac muscle tissue, its main cellular elements - cardiomyocytes, their interconnection patterns, intercalary discs, and the specific mechanism of contraction of the heart. It also highlights the importance of modern histological and immunohistochemical research methods in the study of cardiac muscle tissue.