Nephrotic syndrome (NS) is one of the common renal diseases in children. It is characterized by the presence of proteinuria, hypoproteinemia, edema, and hyperlipedaemia. The aim of this study is to predict the response to steroids and the underlying renal histological diagnosis in NS using SI and to evaluate the accuracy of SI test using serum and urinary transferrin and IgG and its correlation with 24 hours protein in urine.Based on above assumption, our study was organized, to find out, a non-invasive mean; using transferrin and IgG selectivity index to eliminate the group of steroid resistant NS children at first presentation, to avoid using an invasive diagnostic biopsy and to save them waiting for 4 weeks of un- coming steroid response, hence the early use of immuno-suppressive drugs may improve their outcome. To evaluate the efficacy of SI.