Using multifactorial and monolocus models interrelations of a number of constitutional factors of probands (sex, child convulsive reactions, character abnormalities, age at the time of illness onset) with genetic factors of epilepsy occurrence among relatives (365 families) and populations from 5 regions of the Khabarovsk krai (2.88 patients per 1000 subjects) were studied. The dependence of epilepsy manifestation probability in mutant homo- and heterozygotes on sex, convulsive reactions and age characteristics of the proband body reactivity was shown. The notions of double threshold determination of convulsive readiness (the T1 threshold "cuts" a part of population with non-paroxysmal abnormality of the brain bioelectric activity, while the T2 threshold "cuts" that with convulsive reactions) were substantiated, the presence of this causing epilepsy development in individuals with a mutant allele of the major dominant gene. The hypothesis of the ecogenetic interaction of epilepsy main etiologic factors (major gene, environmental factors and constitutional readiness) has been described.