Introduction: Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function, present for more than 3 months with implications for health. Children with CKD have higher mortality rate, which is at least 30-fold higher than their age-matched peers. Glomerular diseases are one of the leading causes of CKD in children. Aim of the study: To assess the clinical utility of urinary nephrin as a diagnostic tool in pediatric patients with glomerular disease (GD) and to evaluate urinary nephrin in assessing the activity and severity of GD in children. Methods: This study was conducted on fifty (50) patients with GD in Pediatric Nephrology Clinic, Childrenʹs Hospital, at Ain Shams University, were further divided into five (5) subgroups according to their diagnosis by renal biopsy. The 5 subgroups included focal segmental glomerulosclerosis (FSGS), minimal change nephrotic syndrome (MCNS), membranoproliferative glomerulonephritis (MPGN), lupus nephritis (LN) and IgA nephropathy. In addition, twenty (20) apparently healthy age and sex matched subjects served as control group. All individuals were subjected to assay of urinary nephrin, kidney function tests, urinary protein/creatinine ratio and complete urine analysis. Results: By comparing the different types of GD, a statistically significant difference was found regarding the urinary nephrin concentration in MCNS subgroup in comparison to FSGS (p < 0.05) and to MPGN (p < 0.05) subgroups. However, no significant difference was revealed between urinary Protein/Creatinine ratio in MCNS subgroup in comparison to FSGS and to MPGN subgroups. Based on the results of the study, urinary Nephrin has the potential to be a crucial sensitive marker for detection of glomerular injury. Nephrin can discriminate between steroid-sensitive nephrotic syndrome (SSNS) and steroid-resistant nephrotic syndrome (SRNS), so it can be used as a noninvasive diagnostic (p < 0.01) marker for SSNS and SRNS in children. Furthermore, urinary nephrin assessment can be of clinical utility in assessing the activity and severity of GD in children. Conclusion: The present study indicates that determination of urinary nephrin can be used as a potential non-invasive marker for diagnosis of GD. Further improvement of its diagnostic efficiency might be reached using nephrin together with protein/creatinine ratio. Moreover, nephrin testing have" the potential to be a promising diagnostic marker since it can discriminate between the steroid-sensitive and steroid-resistant nephrotic syndrome, and thus, nephrin can avoid the non-beneficial usage of steroids -with its adverse effects- in such resistant cases. The best diagnostic cut off level for Nephrin was 5.5 ng/dL.