Background: Diabetic nephropathy (DN) is the primary cause of end-stage renal disease in children with type 1 diabetes mellitus (T1DM), and it can be prevented. Therefore, it is critical to identify children who are at risk of developing DN as soon as possible. Diabetic nephropathy (DN) can be diagnosed using pentosidine and renal resistance index. Aim of this study: to elaborate the significance of serum pentosidine and renal resistance index as early indicators of Diabetic kidney disease (DKD) in type1 diabetes mellitus(T1DM) pediatric patients. Methods: This cross-sectional study was conducted on 48 diabetic children at the pediatric outpatient clinics of Zagazig University Hospitals. Comprehensive assessments included medical history, physical examinations, renal resistance index using doppler sonography, and laboratory tests, including hemoglobin A1C (HbA1C), serum creatinine, microalbuminuria, and serum pentosidine. Results: Serum pentosidine had high diagnostic accuracy for early-stage diabetic nephropathy, with a sensitivity of 90%, a specificity of 97.4%, and an area under the curve (AUC) of 0.964. The mean renal index measured by Doppler sonography was 0.68, indicating a significant relationship with earlystage diabetic kidney disease. The pentosidine and mean resistance index were significantly positively correlated with age, duration of the disease, estimated glomerular filtration rate, and HbA1C. Conclusion: The serum pentosidine level and renal resistance index are reliable early predictors of renal damage in pediatric patients with type 1 diabetes mellitus. To avoid progression to end-stage renal disease, it is crucial to identify children at risk promptly and initiate preventative measures.