A method of growing Bdellovibrio bacteriovorus (Bdv) based on the use of the host microbe in the state of reduced vital activity permitted to obtain Bdv cultures which could be used for the preparation specific antisera. Immunochemical analysis of 4 Bdv strains showed them to possess individual antigenic components localized in the alpha 2-globulin zone. Testing 17 Bdv strains isolated from natural water bodies showed 11 of them to form precipitation lines with the antisera to 4 Bdv strains.