Forty-five marasmic infants were studied for plasma zinc and copper levels. They were selected from those children admitted to a nutritional recovery center. The mean plasma zinc level was 92.4 +/- 24 micrograms/dl (mean +/- SD); 7% of the infants had low zinc values as defined by zinc less than 70 micrograms/dl. Median copper was 90 micrograms/dl (range 27-172) and 49% of the children had copper levels below 90 micrograms/dl (established as our normal limit). Birth weight, breast feeding and prior hospitalization for acute diarrhea with dehydration were studied as antecedents related to low Cu and Zn. Children with prior diagnosis of acute diarrhea and hospitalization had lower copper levels than those sent from primary care centers. Breast feeding was associated with higher Cu levels. No relationship was found between zinc levels and those antecedents, but differences were found in regard to the degree of malnutrition, season of the year and Zn status. In this investigation no Zn deficiency was found in marasmus cases. Hypocupremia, however, is a very significant problem in marasmic infants, especially when associated with early weaning and the presence of previous hospitalization for acute diarrhea.