To isolate brucellosis causative agent from the blood of patients against the background of antibiotic therapy the authors used for the first time the medium consisting of aminopeptide, beta-globulin agar with glucose, glycerine, and twin-60. No valuable food products--meat, liver--were required to prepare the medium; by-product of gamma-globulin production being used. With the aid of the suggested medium there was isolated 2.4 times more hemocultures than on the widely used meat-peptone medium. This is attributed to the presence in the medium of human protein, essential amino acids, and blood mineral substances, which, in combination, facilitated adaptation of brucellosis causative agent to the nutrient medium similar to human blood by composition. Economical effect in using the mentioned medium constituted 53.8% annually.