The monitoring of heavy metals is important if adverse effects on health are to be avoided. In humans, metallothionein (MT) has been used as a biomonitor for the assessment of cadmium (Cd). In the present study, subjects drawn from the population of Tarragona Province (NE Spain) were investigated. Urinary MT, zinc (Zn), and copper (Cu) concentrations, corrected for creatine concentrations, were determined in 625 samples from healthy subjects aged between 10 and 65 yr. Mean values of MT and Cu in females were higher than those in males, with levels of 29.5 (23.8) vs. 22.7 (24.9) micrograms MT/creatinine (p < 0.001) and 4.8 (6.1) vs 3.4 (4.9) micrograms Cu/g creatinine (p < 0.001). No differences between males and females were observed with respect to urinary Zn: 78.0 (66.4) vs 73.0 (85.5) micrograms/g creatinine, respectively (p = 0.332). Significantly higher MT, Zn, and Cu values were observed in the females aged 15-19 yr and, in the age group of 50-54 yr, only in the Zn and Cu values, when compared with those in males. Significant positive correlations of MT vs Zn and Cu as well as correlations of Zn vs Cu levels were observed in both genders. The present findings confirm the proposed role of MT as a biomonitor of mineral status.