Miners working in the North are exposed to more pronounced effects of unfavourable occupational factors (hand drillers, bulldozer operators, etc.) and are found to have higher morbidity rates. With their longer stay in the North, the incidence of gastrointestinal disorders increases. Among the migrants from the regions with contrasting climatic conditions. (Caucasus, Central Asia), the morbidity is higher than among those from other regions of this country.