In this study serum zinc (Zn) and copper (Cu) levels in children with congestive heart failure (CHF) were evaluated. The mean serum Zn levels of the patients with CHF were 92.9 +/- 18.9 micrograms/100 ml, and they showed a significant decrease when compared to controls (p less than 0.05). The mean serum Cu levels, which were 173.6 +/- 26.6 micrograms/100 ml, showed a significant increase when compared to controls (p less than 0.001). After digoxin therapy, a significant increase in Zn levels and a significant decrease in Cu levels were observed.