Recent evidence shows that apolipoprotein (apo) B, apoB/apoA-I ratio and lipoprotein(a) are better indicators of coronary risk than the conventional lipid profile. The aim of this study was to evaluate the correlation of apoA-I and B, and lipoprotein(a) with myocardial infarction (MI). We performed a cross-sectional study including 208 patients (100 men and 108 women), with and without previous MI evaluated by coronary angiography. The severity of coronary heart disease was scored on the basis of the number and extent of lesions in the coronary arteries. Lipid levels were measured by the enzymatic method and apolipoprotein levels were measured by the immunoturbidimetric method. The MI group had higher plasmatic levels of lipoprotein(a) (0.37±0.28 vs. 0.29±0.23 g/L, p<0.05), apoB (1.13±0.40 vs. 0.84±0.28 g/L, p<0.05) and of the apoB/apoA-I ratio (0.77±0.37 vs. 0.68±0.20, p<0.05) compared to controls. The area under the receiver operating characteristic (ROC) curves (AUC) suggested a good reliability in the diagnose of coronary heart disease for the apoB/apoA-I ratio (0.756, p<0.05), apoB (0.664, p<0.05), lipoprotein(a) (0.652, p<0.05) and total cholesterol/HDL-cholesterol (0.688, p<0.05). Multivariate analysis performed with adjustments for cardiovascular risk factors, showed that the levels of lipoprotein(a), apoB and apoB/apoA-I ratio are significant independent cardiovascular risk factors. Our results indicate that there is an important relationship among high plasma apoB concentration, lipoprotein(a) concentration, the apoB/apoA-I ratio, and MI. We showed that the apoB/apoA-I ratio has a stronger correlation with MI than the total cholesterol/HDL cholesterol ratio. We therefore suggest using apoB/apoA-I ratio and lipoprotein(a) in clinical practice as a markers of MI risk.