Testosterone deficiency is associated with late-onset hypogonadism. Micronutrients including copper (Cu) and zinc (Zn) influence testosterone synthesis. The association between micronutrient concentrations in hair tissue and serum testosterone was studied in Korean men. The subjects were 88 men 40-60 years of age who visited the health promotion center and an outpatient clinic of family medicine at a university hospital from March 2006 to February 2008. Population sociological features of the subjects were acquired by self-administered surveys and interview, height and weight were measured, serum total testosterone was determined in the morning, and Cu and Zn were quantified from hair tissue collected in the morning. Subjects with normal testosterone group had a significantly higher Zn level compared to low testosterone group (P = 0.003). Significant negative correlations were evident between total testosterone and Cu level (r = -0.252, P = 0.022), and the Cu/Zn ratio (r = -0.288, P = 0.008). Normal testosterone is associated with a higher Zn level. Decreased serum testosterone is significantly associated with a high level of Cu and elevated Cu/Zn ratio in hair tissue.