OBJECTIVE:To evaluate the impact of hydroxyurea (HU) on nutritional status and serum 25-hydroxyvitamin D (25-OHD) of children with sickle cell disease (SCD). DESIGN:Anthropometry and serum 25-OHD were determined in 98 children with SCD, comprising of 68 in HU-group and 30 in HU-naive group. RESULTS:Underweight was more common among HU-naive group (33.3% vs. 10.3%, P=0.009), while 79.4% of HU-group against 56.7% HU-naive had normal body mass index percentile for age and sex, P=0.028. None of the HU-group compared with 13.3% of the HU-naive had severe vitamin D deficiency, P=0.002. The mean 25-OHD of the HU-group was also higher (24.1±1.2 vs. 19.1±9.8 ng/mL, P=0.007). CONCLUSIONS:HU possibly ameliorate growth retardation and vitamin D deficiency in children with SCD.