Background: Diabetes mellitus (DM) is a common chronic illness that affects many persons all over the world. Diabetic nephropathy (DN) is a common serious problem that occurs in a considerable percentage of diabetic patients. Renal resistive index (RI) reflects hemodynamics of intrarenal arteries. Objective: Here, we aimed to determine efficacy of RI in prediction of DN. Patients and methods: A cross-sectional study was conducted over one year duration in Nephrology Unit of Internal Medicine Department, Assiut University Hospital. A total of 91 patients with DM were recruited. All patients were evaluated based on history taking, clinical evaluation, laboratory data and renal RI and subdivided into DN group and non-DN group. Results: Out of those patients; 40 (43.9%) patients had DN (DN group) and 51 (56.1%) patients hadn't DN (No-DN group). Patients with DN had significantly longer duration of DM (10.45 ± 1.11 vs. 4.09 ± 0.56 (years); p < 0.001) and higher RI (0.89 ± 0.11 vs. 0.49 ± 0.18; p < /em>< 0.001). Duration of DM (> 5 years), impaired glycemic control and resistive index were predictors for DN among patients with DM. At cutoff point > 0.73, resistive index had 82.5% overall accuracy with area under curve was 0.837 for prediction of diabetic nephropathy. Conclusion: Renal RI reflects hemodynamics of intrarenal arteries in patients with DM and could be used as a promising tool in early identification of DN. Multiple future studies at multiple centers with long term duration of assessment are warranted.