BACKGROUND: The ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene is a candidate gene for insulin resistance. Insulin resistance is a major component of metabolic syndrome (MetS) and has been implicated in ischemic heart disease (IHD). OBJECTIVE: To evaluate the association between the K121Q polymorphism of the ENPP1 gene and IHD in white patients with type 2 diabetes mellitus (DM). METHODS: A cross-sectional study was performed in type 2 DM patients (n = 573, 50.6% males, age 59.5±10.4 years). IHD was defined by the presence of angina or myocardial infarction according to the Worth Health Organization cardiovascular questionnaire and/or compatible electrocardiographic (Minnesota Code), or perfusional abnormalities in myocardial scintigraphy. The K121Q polymorphism of ENPP1 gene was genotyped using PCR-based methods and restriction enzyme digestion. RESULTS: IHD was present in 209 (36.5%) patients. The distribution of KK, KQ and QQ genotypes among patients with IHD was 60.8%, 34.4% and 4.8%, not different from the genotype distribution in the group without IHD (64%, 32.7% and 3.3%, P=0.574). No difference was found in the clinical and laboratory characteristics between the three genotypes, neither regarding the prevalence of Metabolic Syndrome. CONCLUSION: No association was found between polymorphism K121A of ENPP1 gene and the presence of IHD.