Sera of 890 healthy Jinan residents were chosen randomly, and the concentrations of serum Zn and Cu were detected by atomic absorption spectrometry. The mean serum Zn and Cu concentrations and Zn/Cu were 1.32 +/- 0.49 mg/l, 0.99 +/- 0.26 mg/l, and 1.41 +/- 0.56, respectively. Significantly higher levels of serum Zn and Zn/Cu but lower serum Cu were found in the men. Descending tendency of serum Zn and Zn/Cu was observed with social-economic status and age but not significant. Alcohol consumption produced higher level of serum Zn and Zn/Cu but lower Cu concentration. Smoking caused significant lower level in serum Cu concentration but no significance in serum Zn and Zn/Cu. Serum Zn and Zn/Cu were normal only when hours of sleep a night were kept within 7-9 h. Higher level of serum Zn and Cu concentrations and Zn/Cu were observed in individuals with regular physical exercise, but still no significant difference existed. No clear relationship between educational levels with serum Zn and Cu concentrations and Zn/Cu was observed.