The peculiarities of HLA class II profile and lipid metabolism were examined in Buryat and Russian ethnic groups of patients with diabetes mellitus type 1. The incidence of type 1 haplotypes in HLA class II gene family was lower in Buryats than that in Russians. In comparison with Russians, the course of diabetes mellitus type 1 in Buryat patients was characterized with a lower content of total lipids, triacylglycerols, total cholesterol, and LDL, which probably explains a more favorable course of the disease in Buryat population.