In order to develop the tentative criteria of the differential diagnosis, 18 patients with obstructive hypertrophic cardiomyopathy (OHCMP), 3 with nonobstructive hypertrophic cardiomyopathy (NOHCMP), 8 with essential hypertension (EH) with inadequate left ventricular hypertrophy (LVH) and 10 normal persons were subjected to clinical examination and to ultracardiosonography. The patients with OHCMP mainly complained of dizziness and syncopes. Since childhood they had systolic murmur and ECG abnormalities. Ultracardiosonography showed asymmetrical LVH, a considerable decrease of the ventricular cavity as well as abnormalities of the localization and function of the papillary muscles. NOHCMP was marked by the combination of the good well-being of the patients with gross abnormalities on the ECG. Ultracardiosonography demonstrated moderately pronounced and asymmetrical LVH. The group suffering from EH with inadequate LVH was characterized by the early development of severe circulatory failure with arterial hypertension of moderate intensity. The changes in the architectonics of the left ventricle and its subvalvular structures turned out to be similar to those in OHCMP but were less remarkable.