We investigated 22 infants with sepsis syndrome, 16 infants with either upper respiratory or urinary tract infection (URTI+UTI), and 11 healthy infants with the purpose of evaluating serum zinc, copper levels, and copper/zinc ratios. Serum zinc and copper levels were lower in infants with sepsis compared to healthy infants and infants with mild infection, but the differences were not significant. We also found very low serum zinc levels in septic nonsurvivors (below 10.7 mu mol/L, in 4 of 6 cases). Serum zinc levels after therapy in sepsis survivors were found to increase significantly compared to initial levels. We concluded that: (1) serum zinc and copper levels decreased by a correlation of the severity of infection, and (2) the measurement of serum zinc levels may be a prognostic indicator of sepsis in infancy. J. Trace. Elem. Exp. Med. 13:265-270, 2000. (C) 2000 Wiley-Liss, Inc.