Characteristics of left ventricular hypertrophy (LVH) were investigated in random samples of the Chukotka coastal Native population (131 males) and in the urban Novosibirsk population (627 males) aged 30-59. Standard epidemiological methods employing electrocardiography (EKG) and echocardiography (EchoCG) were used. The frequency of EKG-LVH in the urban population was about six percent. The prevalence of LVH in Chukotka was more than twice as high as in Novosibirsk, as determined by both EKG and EchoCG criteria. About half of EchoCG-LVH cases in Natives and one-fifth of those in the city population could not be explained by conventional reasons. Advanced family surveys in Novosibirsk established the fact that myocardial hypertrophy exhibits a family aggregation in first-degree relatives of normotensive probands affected by LVH. The data demonstrate an inherited predisposition for LVH and suggest the need for molecular-genetic analysis.