It has been suggested that homocysteine (tHcy) levels and methylenetetrahydrofolate reductase (MTHFR) genotype are primary risk factors for coronary heart disease (CHD). We performed a case-control study to investigate whether tHcy levels and MTHFR genotype (677 C-->T mutation and 1298 A-->C mutation) are associated with CHD under special consideration of the possibility for confounding.