Nephropathic cystinosis is an autosomal recessive lysosomal storage diseaseresulting from defective export of cystine from lysosomes all over the body; leadingto tubular dysfunction, growth failure, progressive loss of glomerular functions,photophobia and hypothyroidism as early manifestations. Early diagnosis andoptimal treatment with cysteamine results in long term depletion of lysosomalcystine. In the current work, effect of cysteamine therapy was assessed in 8 childrenfollowing at Inherited Renal Disease Clinic and we found that early and optimalcysteamine therapy could reserve glomerular functions, delay the development ofESRD and improve the growth velocity in these children.