The purpose of this study was to evaluate the influence of different factors, among them left ventricular hypertrophy (LVH) on long-term heart rate variability (HRV) in patients with hypertension. 38 patients with arterial hypertension of different genesis were included in the study. Ischemia was excluded in all the patients by the data of clinical and instrumental methods of investigation. LVH data obtained from HRV of 20 healthy subjects was used as control. HRV was evaluated by estimating variations for short intervals of a rhythmogram (VSI). A HRV decrease did not depend on sex, but essentially depended on patients\'a age, disease duration and the form of hypertension. A marked tendency leading to the rate variability decrease was observed only in moderate LVH. In cases of original LVH variability data did not differ from those in patients without signs of LVH. Low or marginal HRV was more often observed in patients with essential hypertension and in those with hypertension of endocrine genesis. As far as renal hypertension is concerned low variability was less frequent. There were a lot of factors which affect the change of HRV. The more significant of them were the patients\' age, hypertension genesis and form of hypertension. Factors leading to the rate variability decrease were the following age above 40, endocrine or essential hypertension and moderate form of hypertension.