Zinc deficiency is a cause of growth retardation in children. The abnormal Zn turnover in Sickle Cell Disease (SCD) has been associated with failure to thrive but the impact of Zn supplementation in children with this disease is not well defined. To evaluate thus, 29 children with SCD (14 girls and 15 boys), mean age 7.6 y (2 to 14y), without hepatic diseases or other clinical complications were studied during a mean period of 11.4 months. Children were divided into 2 groups: 14 children (GI) received a daily dose of 7mg ZnSo4 5% p.o. and the remaining 15 (GII) were not supplemented. A third group (control) was constituted by 9 children (4 girls and 5 boys), sibblings of the patients: 5 of them, received Zn supplementation (GIII) and 4 were not supplemented(GIV). A 24hour dietary recall evaluated caloric, proteic, and Zn intake at the beginning and at the end of the study. Anthropometric measurements (weight and height) were obtained to calculate growth velocity. Laboratory evaluation consisted of serum Zn, proteins, FV, and Hb/Ht. Energy and Zn intakes were similar in all groups and below the recommendations, protein intake was adequate (GI=5.57mg Zn; 1544kcal/d; GII=4,48mg Zn; 1565kcal/d; GIII=6.03mg Zn; 1427kcal/d; GIV=6.01mg Zn; 2514kcal/d). Mean values of final and initial H/AZ scores were similar in the 4 groups (GI=1.1±0,9; -1,2±0,8; GII=-0,1±1,6; -0,3±1,2; GIII=-0,1±0,9; 0,0±0,8; GIV=0,4±0,3; 0,5±0,7). Linear regression of H/A Z score variations and the time of follow up was not significant in any of the studied groups. Final H/A Z scores in SCD children were lower than in their healthy siblings, regardless Zn supplementation (GI+GII=-0,7±1,1; GII+GIV=0,2±0,8). W/A Z scores increased significantly in GI as compared with GII (GI=0,08±0.1; GII=0,2±0.49; p<0.05). Laboratory measurements were similar in the 4 groups. In conclusion, the use of 7mg/day of Zn supplementation did not promote catch up growth in SCD children or in the control groups. Low energy intake may be responsible at least in part for the growth retardation observed in SCD children.