OBJECTIVE The underlying mechanism of atherosclerosis and visceral obesity remains unknown.The purpose of this study was to test the hypothesis that atherosclerosis and visceral obesity are caused by an immune response to native plasma lipoproteins, and the atherogenic and adipogenic effects of the antibodies to native lipoproteins stem from the androgen deficiency that is created. METHODS Wistar rats were immunized with native human (nh) low-density (LDL) or high-density lipoproteins (HDL). Visceral fat, aortic wall structure, and testosterone levels were studied. RESULTS Immunization with nhLDL or nhHDL induced in rats increased visceral abdominal fat and perivascular adipose tissue volume, the appearance of epicardial fat, and atherosclerosis-like changes in the aortic wall: accumulation of leucocytes, destruction of the intima, and disruption of the media structure. Immunized rats produced antibodies to native plasma lipoproteins, while there was no difference between immunized and adjuvant-injected rats with regard to the level of antibodies to oxidized LDL. The immune response to nhHDL caused testosterone disturbances, but it is not associated with visceral obesity and atherosclerosis. CONCLUSIONS The immune response to native lipoproteins is atherogenic and adipogenic and testosterone is not involved in the atherogenic and adipogenic effects of antibodies to lipoproteins.