We evaluated the effect of one year of supplementation with iron plus zinc (12 mg/day of Fe+++ and 12.5 mg/day of Zn++), zinc alone (12.5 mg/day of Zn++) and placebo on growth and on the iron, zinc, copper and selenium tissue contents in 30 well-selected children of short stature (16 M and 14 F; 4-11 years old). Before and after supplementation, we measured the concentrations of iron, transferrin, ferritin, zinc and copper in serum, of zinc in erythrocytes and leukocytes, and of zinc, copper and selenium in hair, as well as glutathione peroxidase activity in erythrocytes. Before supplementation, ferritin and serum, erythrocyte and hair zinc contents were significantly lower than in age-matched controls, while the other measured indices were in the normal range. Iron plus zinc supplementation caused an improvement in growth rate in all subjects, i.e., the median Z-score increased from -2.22 +/- 0.45 to -0.64 +/- 0.55; (p < 0.01). In the zinc-supplemented group, only the subjects whose ferritin levels were higher than 20 ng/L before supplementation showed a similar improvement of growth rate. Iron plus zinc supplementation could be a reasonable treatment in short, prepubertal children affected by marginal zinc and iron deficiency.