19 kidney allografts patients had repeated biopsies for clinical purposes and parallel MRI examinations. There was no significant correlation between eGFR and renal interstitial fibrosis (IF) at baseline, whereas baseline deltaADC (a MRI derived parameter sensitive to the water diffusion in the tissue) correlated. negatively to renal interstitial fibrosis (IF). Considering the difference between the basal and follow-up values, there was a good correlation between the evolution of IF and deltaADC but not between the evolution of IF and eGFR. These results suggest that deltaADC may be more reliable than eGFR to allow earlier detection of an increase in IF.