Paraoxonases (PONs) may exert anti-atherogenic action by reducing lipid peroxidation. We evaluated the influence of 2 polymorphisms within PON1 (192 Gln/ Arg) and PON2 (311 Ser/Cys) genes in 407 young Poles: 273 patients who experienced a first myocardial infarction (MI) under the age of 45 (study group) and 134 healthy volunteers (control group) with a HEART Score < or =2 (low risk). Paraoxonase 1 polymorphism 192Gln/Arg influenced the risk of premature MI (P = .0054). A positive family history of coronary artery disease (CAD) was associated with the 192Arg allele (P = .0107). The association between PON1 genotype (192 Gln/Arg) and low-density lipoprotein cholesterol (LDL-C) (P = .036) levels was also observed. However, we did not find any relationship between polymorphism 311Ser/Cys and CAD risk (P = .418). PON1 polymorphism 192Gln/Arg influenced the risk of premature MI. The association between PON1 genotype (192 Gln/Arg) and serum LDL-C levels may be explained by PON participation in reverse cholesterol transport.