Renal dysfunction is a worldwide problem; and a non-invasive assessment is required for planning treatment and follow-up. Human kidney is one of the well-perfused organs,¹ and its major function is related to water transportation (glomerular filtration, active and passive tubular reabsorption) under normal conditions.² Intra-voxel incoherent motion (IVIM) can isolate fast from slow water motion in well-perfused organs and may be helpful in assessing renal dysfunction compared with a mono-exponential model.To evaluate IVIM in the assessment of renal dysfunction compared with a mono-exponential model.Fifty-four subjects were enrolled into this study. The estimated glomerular filtration rate (eGFR) was assessed to classify the subjects as having severe renal injury group (sRI, eGFR < 30 ml/min/1.73 m²) or not (non-sRI). A free-breathing DWI with 7 b-factors was performed. A radiologist conducted Image analysis. An apparent diffusion coefficient map (ADC_mon) was generated in mono-exponential model, and diffusion coefficient (D_slow and D_fast), and fraction of fast diffusion (F_fast) maps were generated in IVIM. The small circular regions of interest were placed at the interface between the cortex and medulla for parameter measurements.All four parameters (ADC_mon, D_slow, D_fast, and F_fast) were less in sRI than non-sRI (P<0.05). However, only both ADC_mon and D_slow were linearly related with eGFR (P<0.05). For differentiating sRI from non-sRI using the four parameters, receiver operating characteristic curve analysis shown no significant difference was present between them (P>0.05). Furthermore, the correlation was 0.93 between ADC_mon and D_slow, larger than 0.57 between D_fast and F_fast, 0.48 between ADC_mon and D_fast, and 0.34 between ADC_mon and F_fast (P<0.05).IVIM model can differentiate sRI from non-sRI, but ADC_mon, a combination of fast and slow diffusion, might be more suitable as a biomarker image for assessing renal dysfunction.