The subject of investigation was the comparison of HLA antigen distribution in people with borderline hypertension (BH) and essential hypertension (EH). One hundred twenty-one men with BH and 60 men with EH were studied. The HLA frequency was compared with that in 858 healthy men, who were blood donors. In BH the increase of B16, B18, and Cw4 and the decrease of A11 and B5 antigen frequency were found. In comparison with St. Petersburg's healthy population, patients with EH were characterized by increasing antigens B18, B41, Cw2, and Cw4 frequency. The coincidence of increased antigen B18 and Cw4 representation in BH and EH allows us to consider them to be immunogenetic markers or predictors of development of EH.