BACKGROUND: We analyzed the data obtained from regular health checkups performed in a university hospital and investigated the effect of serum gamma-GT on hypertension for both Korean males and females. METHODS: A total of 3,288 adult males and females over 20 years of age were selected for this study who visited a health promotion center from April, 2004 to April, 2005. Patients with HBs Ag (+) or anti-HCV Ab (+) and those currently on medication that could affect hepatic function were excluded. The subjects' history of illness and their present health and medication status were examined through questionnaires and history taking. Also, basic physical examinations and laboratory tests were performed on these subjects. RESULTS: Classifying the serum gamma-GT into quartiles, as the gamma-GT classification stage increased, there was an increase in the amount of smoking, alcohol, body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, fasting glucose, total cholesterol, triglyceride and low density lipoprotein for males or female (respectively, P for trend <0.01). When odd ratio (95% CI) for hypertension in the highest quartile of gamma-GT was compared to that of the lowest quartile, there was an increased risk of hypertension with an odd ratio of 1.6 (95% CI, 1.0~2.3) and 1.6 (95% CI, 1.0~2.4) for males and females, respectively. CONCLUSION: This study showed that the risk of hypertension was increased according to serum gamma-GT, even though the variable index affecting cardiovascular diseases was adjusted.