Abstract Background: The transplanted kidney is very precious and all efforts should be made to prolong its survival rate. However, graft rejection is one of the serious problems to long-term kidney transplant survival. Aim of Study: The main aim of this study is to correlate between color Doppler findings and histopathological results of graft biopsy in post renal transplantation rejection patients. Patients and Methods: This cross section study was performed on 35 renal transplant recipients, within two years of transplantation and was recruited after recent rise in renal function tests. Results: The study was performed on 21 males (67.7%) and 10 females (32.3%). 8 patients had hypertension (25.8%) and 5 patients were diabetic (16%). The serum creatinine level of the patients ranged from 1.6 to 7.2mg/dl (mean 3.07±1.21mg/dl). The serum urea level ranged from 44 to 79mg/dl (mean 63.55 mg/dl). Use of immunosuppressive drugs: 12 patients used tacrolimus out of 31 (38.7%) while 19 patients out of 31 used cyclosporine (61.29%). Doppler findings: RI in the main renal artery ranged from 0.60 to 1 (mean 0.80±0.8), RI in the interlobar artery ranged from 0.53 to 1 (mean 0.76±0.1). The PI of main renal artery ranged from 1 to 2.49 (mean 1.76±0.34). Classification was done according to Banff system corresponding to results of renal biopsy. Conclusion: With agreements to many studies, this study supports the fact that ultrasound imaging is a key method of post-transplant monitoring in kidney transplantation patients with the benefits of gray scale ultrasound and Color Doppler as noninvasive, simple and cost effective screening modalities for renal transplant evaluation, adding to that early prediction of transplant rejection & its correlation with histopathological results.