Diabetic nephropathy (DN) is considered the most frequent cause of end-stage renal disease (ESRD). For early diagnosis and follow up of renal function in patient with established DN, Duplex Doppler Sonography can be used as noninvasive tool. The aim and objective of the study was to determine whether resistive index could remain higher in type 2 diabetic patients having nephropathy in comparison with that of non-diabetic controls. This case-control study was done in the department of Radiology and Imaging, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM) from 1st Octy 2014 to 30th June 2015. Total 65 diabetic nephropathy patients were taken as study group and 65 healthy subjects were included as healthy control subjects. Duplex Color Doppler sonography of interlobar artery was carried out in both groups for the measurement of Peak systolic velocity, end diastolic velocity and arterial Resistive Index (RI). The RI of interlobar artery of left kidney in control group was 0.58±0.08 (mean±SD) and the mean RI of interlobar artery of left kidney in diabetic nephropathy patients was 0.74±0.53 (mean±SD). The difference of RI of interlobar artery of left kidney in the two groups was statistically significant and the RI of right kidney of control and that of case groups were 0.60±0.09 and 0.76±0.031 (mean±SD) respectively. In between control and case groups the RI of right kidney was statistically significant (p = <0.5). So, resistive index of interlobar artery was increased in type 2 diabetic nephropathy patients in comparison to control group. Study findings reveal that resistive index remains significantly higher in patients with diabetic nephropathy than control group. For this reason, RI can be used for early diagnosis of diabetic nephropathy by Duplex Doppler ultrasonography.