Zinc (Zn) is an essential trace element for humans and its deficiency can lead to several clinical problems. This study examined the relationship between the serum zinc concentration and anemia in middle-aged and elderly people. Samples were obtained from 150 men and 303 women who received health checkups over the course of 40 years. The serum concentration of Zn was measured as well as the complete blood count (CBC), alanine aminotransferase (AST), aspartate aminotransferase (ALT), gamma-glutamyl transferase (gamma GT), total cholesterol (TC), high density lipoprotein (HDL-C), triglyceride (TG), creatinine (Cr), uric acid (UA) and fasting plasma glucose (FPG). The serum Zn concentration was 77.4 +/- 9.7 microg/dL in men and 79.1 +/- 10.4 microg/dL in women (p= 0.09). The serum Zn concentration correlated inversely with age (r=-0.11, p=0.018). Anemia diagnosed by the World Health Organization criteria, was present in 17.3% of men and in 13.5% of women. However, more than 80% of the anemia was normocytic (men 86%, women 81%). The serum Zn concentration was significantly lower in those with anemia than in those without anemia. The Hb level correlated with the serum Zn concentration (men r=0.25, p=0.002, women r=0.23, p<0.001). A multiple regression analysis confirmed a low serum Zn concentration to be associated with a low Hb level. In conclusion, this study indicates that the serum Zn concentration decreases with age and that a low Zn concentration is associated with normocytic anemia, thus suggesting that a Zn deficiency may therefore be one of the causes of anemia in elderly people.