This study has been done with 1,431 subjects who visited Health Promotion Centers of the hospitals in Gumi for National Health Screening Program for People at Transitional Ages from April to December 2007. Serum biochemical tests related with metabolic syndrome were performed. Among biochemical factors related with metabolic syndrome, the mean values of serum glucose, AST, ALT, triglyceride and HDL cholesterol except LDL cholesterol were significantly higher in males than in females, so a significant difference by sex was observed (P<0.001). AST, ALT, triglyceride and HDL were thought to be significantly affecting serum GGT for males. In contrast, ALT and HDL cholesterol were important factors for females (P<0.001). For both sexes, serum glucose and LDL cholesterol did not produce any meaningful effect on serum GGT. In males AST, ALT and HDL cholesterol were associated with high risk of abnormality of serum GGT and in females AST, ALT and LDL cholesterol were related with high risk of abnormality of serum GGT. Therefore, AST and ALT showed a significant effect on abnormality of serum GGT in both males and females. It was observed that males exhibited significantly high correlation between metabolic syndrome related biochemical factors and serum GGT than females, and their influence on abnormality of serum GGT was also higher in males than in females. Therefore, serum GGT tests performed for health screening are considered to be useful for managements of cardiovascular diseases and metabolic syndrome as well as liver function test.