During the last decade, a growing corpus of evidence has indicated an important role of cytokines in the development of brain damage following cerebral ischemia. Tumor necrosis factor-alpha (TNF-alpha), a potent immunomodulator and pro-inflammatory cytokine, has been implicated in many pathological processes. In this study, we examined whether promoter region polymorphism in the TNF-alpha gene at position -308 affects the odds of cerebral infarction (CI) and whether genetic risk is enhanced by Sasang constitutional classification. Two hundred and twelve CI patients and 610 healthy controls were genotyped and determined according to Sasang constitutional classification. A significant decrease was found for the TNF-alpha A allele in CI patients compared with controls (p = 0.033, odds ratio, OR: 0.622). However, there was no significant association between TNF-alpha polymorphism and Sasang constitution in CI patients. Our finding suggests that TNF-alpha promoter region polymorphism is responsible for susceptibility to CI in Koreans.