Objectives: We tried to clarify the relationship between lifestyle and plasma homocysteine concentration. We analyzed the data of patients with acute ischemic stroke from the Hanbang stroke registry supported by the Ministry of Science and Technology of Korea. Methods: 458 subjects were recruited from the patients admitted to the Internal Medical Department of Kyunghee University oriental medical center, Dongguk University Ilsan oriental medical center, Kyungwon University Songpa oriental medical center and Kyungwon University Incheon oriental medical center from April 2007 to August 2008. We divided the subjects into four groups by quartiles of plasma homocysteine concentrations and compared the first and last quartile groups. Results: 1. In univariate analysis, the high homocysteine concentration group showed higher rate of older age, male gender, smoking, drinking and lower values in vitamin B12, folic acid, creatinine than the control group with statistical significance. 2. In multivariate analysis, older age, male gender smoking and folic acid showed a close relationship with statistical significance (each OR=3.620, OR=4.218, OR=3.558, OR=0.789). Conclusions: According to the analysis, the relationship between high homocysteine concentration and smoking in patients with acute ischemic stroke were clarified. We hope to standardize and establish criteria on homocysteine in Korea by large epidemiological survey. These study results could be utilized in the future as a basis material.