The material analysed is referred to 5 goiter endemic microfoci of one of the landscape-geographical zone of the Kama region with a relative iodine deficiency in the environment, caused by disbalance between iodine and other trace elements. Diffuse enlargement of the thyroid gland was revealed in 50.5% of males, and in 69.7% of females; goiter disease was diagnosed in 3.3% of males, and in 11.6% of females. The empirical risk of goiter occurrence for members of the family with one patient suffering from this disease is double, and in the families with two or more patients--is four tunes greater than in the rest of the population. There proved to be statistically significant differences in goiter morbidity among persons with different degree of blood relation to the proband. Calculations by the original method presented demonstrated that familial associations of goiter patients corresponded to monomere autosome-dominant inheritance with an incomplete manifestation of the corresponding genotype within the range of P = 0.7--0.8.