The results of a medical genetic survey of the population of four raions (176 535 individuals) of Rostov oblast (Dubovsky, Zimovnikovsky, Myasnikovsky, and Krasnosulinsky raions) are presented. The load of autosomal dominant (AD), autosomal recessive (AR), and X-linked hereditary diseases for urban and rural population was calculated, and the diversity of monogenic hereditary diseases (MHD) was reviewed. The nosological spectrum of MHD constituted 117 diseases (63 diseases with AD inheritance; 38 with AR inheritance; and 16 with X-linked inheritance). The analysis showed that the incidence of MHD among the population of Rostov oblast was 1 : 336. Considerable differentiation in the prevalence rates of MHD (AD, AR, and X-linked pathologies) among certain raions was revealed.