BACKGROUND: Many previous studies have shown that elevated homocysteine in the serum is a well known risk factor for cardiovascular disease and this is associated with other risk factors for cardiovascular disease, but any Korean data on this is limited. OBJECTIVES: This study aimed to calculate the prevalence of hyperhomocysteinemia and to analyze the relation between elevated homocysteine and the lifestyle factors of Korean adults. METHODS: We conducted a cross-sectional survey that included 650 men and 743 women (age range, 20 to 79 years) who were residents of Gwangju City in Gyeonggi-do. These subjects participated in the health interview and examination survey from November to December 2005. The total homocysteine, total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride in the serum were measured. All the participants had their body composition measured such as height and weight, and we obtained health-related behavioral information through the self-entry questionnaire. RESULTS: Very right-handed skewed distributions of homocysteine were shown in men and women. The prevalence of hyperhomocysteinemia was 22.6% in men and 13.7% in women in Gwangju city. On the multiple logistic regression analysis, hyperhomocysteinemia was associated with age (OR=1.02, 95% CI=1.01-1.04), male gender (OR=1.60, 95% CI=1.02-2.52), severe general physical activity (OR=0.32, 95% CI=0.15-0.69) and nutrient consumption (OR=0.49, 95% CI=0.31-0.76). CONCLUSIONS: There is a great prevalence of hyperhomocysteinemia in adults of Gwangju City, Korea and it was associated with both genetic factors and lifestyle risk factors. This study can suggest that comprehensive lifestyle modification is needed in order to diminish the prevalence of hyperhomocysteinemia and to prevent CVD.