The purpose of this study was to investigate the effects of micronutrient supplementation on the growth of preschool children in China. A double-blind, placebo-controlled trial was conducted on 156 growth retarded preschool children who were randomly assigned to the following five groups : supplemental control (S-control; n=28); zinc supplementation (＋Zn; 3.5mg Zn/day, n=34); zinc and calcium supplementation (＋ZnCa; 3.5mg Zn ＋ 250mg Ca/day, n=37); zinc, calcium and vitamin A supplementation (＋ZnCaVA; 3.5mgZn ＋ 250mgCa ＋ 200gVA/day, n=28); and calcium and vitamin A supplementation (＋CaVA; 250mgCa ＋ 200gVA/day, n=29). Another 34 children of normal height were selected as a normal control (N-control). Supplementation continued for twelve months. After supplementation, the height gains in the ＋Zn group (7.84cm per year) and the ＋ZnCa group (7.70 cm per year) were significantly higher than that in the S-control group (6.74 cm per year, P＜0.05). The weight gain in the ＋ZnCaVA group (2.55kg per year) and the ＋CaVA group (2.57 kg per year) was also significantly higher than that in the S-control group (2.19 kg per year, P＜0.05). The average number of days of illness in each group taking supplements was lower than that in the S-control group (13 days per year compared with 23 days per year). No significant differences in bone maturity were observed between the groups. In conclusion, in this study Zinc and Zinc ＋ Calcium supplementation improved the height gain, and vitamin A improved the weight gain, in growth retarded preschool children, but these supplements did not affect the maturity of bone. Micronutrient supplementation also lowered the morbidity of these children.