The relationship between autoantibodies (autoAbs) to oxidized LDL (oxLDL) and coronary artery disease (CAD) remains controversial. IgM and IgG autoAbs to oxLDL and 1-palmitoyl-2 (5'-oxo-valeroyl)-sn-glycero-3-phosphorylcholine (POVPC), as well as the levels of non modified or modified ApoB-100 immune complexes (ICs), were measured in twenty patients undergoing clinically indicated coronary angiography, and in ten young healthy volunteer sera. The levels of IgM autoAbs to oxLDL did not differ between no CAD patients and healthy subjects, but the levels of these autoAbs were significantly higher in no CAD patients and healthy subjects in comparison with CAD patients. There was not difference in the levels of IgM anti-ApoB-100 ICs between both groups of patients. In contrast, the levels of ICs formed by IgM autoAbs and oxidative modified ApoB-100 were lower in patients with CAD than in patients without CAD. No differences were observed in the levels of autoAbs to POVPC among the groups. In conclusion, our results showed that the level of circulating oxLDL IgM autoAbs was lower in CAD patients than in no CAD patients, supporting the hypothesis that this kind of autoAbs might be inversely associated with the presence of atherosclerosis.