History and Objectives: Due to the prevalence of children with height and weight levels lower than 50 percentile in Iran and considering the importance of Zinc in the health of children and the prevalence of Zinc deficiency and nutritional Zinc deficiency syndrome and in order to define the effect of supplemental Zinc on weight and height percentiles of children, this research was conducted on the referrers to Masih Daneshvari hospital during the years 1376 to 1378.

Materials and Methods: This study was performed by clinical trial method with comparison before and after the performance of the study. Age, sex, weight and height percentiles of children were evaluated before and after administration of supplemental Zinc. Supplemental Zinc (Merck Company Germany) was administered as a 0.5% Zinc sulfate solution at a dose of 3 mg/kg and serum Zinc level was measured at atomic energy organization by atomic absorption spectrophotometry method. Changes in the percentiles were calculated with MC Nemar’s test and the role of age, sex, the initial Zinc level on the percentile changes and also their relative risk were calculated.

Results: This study was performed on 42 individuals including 21 girls and 21 boys aged 4.9±4.1 years old and weighed 16.5±8.1 kilograms with a height of 101.8±23 centimeters the initial Zinc level was 85.1±31.6 microgram per deciliter. The duration of Zinc administration was 3.2±2.6 months and the patients were followed from one to 10 months. Children whose weight was below 50 percentile decreased from 69% to 54% (P<0.05) and those with a height less than 50 percentile decreased from 50% to 33% (P<0.01) and the percentile change were more significant in those children whose initial serum Zinc level was lower. This condition was more commonly observed in boys.

Conclusion: The supplemental Zinc was more effective when administered to children less than five years old. If supplemental Zinc be administered at an earlier age for girls. There is a better chance for increase in height and weight.