Abstract: AIM:To investigate the association between IL-18 promoter functional polymorphisms (-607C/A and -137G/C) and myocardial infarction (MI) in a Han population of northern China. METHODS: A case-control study was conducted in 468 patients with MI and 432 controls with normal results of coronary angiograms. Genotyping was performed by sequence-specific primer-polymerase chain reaction. RESULTS: Genotype frequencies of CC, CA and AA of the IL-18 -607C/A polymorphism were, respectively, 20.83%, 50.93% and 28.24% in the controls, and 36.32%, 44.87% and 18.81% in MI patients. Genotype frequencies of GG, GC and CC of the IL-18 -137G/C polymorphism were, respectively, 71.30%, 26.85% and 1.85% in controls and 75.21%, 23.93% and 0.86% in MI patients. Significant differences were observed in the genotype and allele distribution of -607C/A polymorphism of the IL-18 gene between cases and controls (P<0.05). Logistic regression analysis with adjustments for other well-established risk factors revealed that the -607C allele carriers had a significantly increased risk of MI compared with the non-carriers (P<0.05). No relationship between -137G/C polymorphism and MI was found in this study (P=0.133). Compared with the AC haplotype, the CG haplotype was associated with reduced occurrence of MI. CONCLUSIONS: This study shows for the first time that the IL-18 gene promoter -607C/A polymorphism can be considered a genetic risk factor for MI in a Han population of northerb China. CG haplotype is associated with MI occurrence.