Kidney transplantation is the treatment of choice for patients with end-stage renal disease. However, it is associated with serious potential complications, one of which is the subcapsular renal transplant hematoma. Ultrasound is the major imaging tools in the evaluation of early graft complications. We discuss the case of a patient who underwent a living-donor kidney transplantation, complicated of acute kidney injury documented on serial blood tests with an elevation of creatinine levels and oliguria. Ultrasonography showed the presence of a subcapsular renal hematoma, associated with the same spectral characterizations of an acute tubular necrosis with a high resistive index on Color Doppler Ultrasonography Study of renal arteries. The patient underwent an emergent surgical evacuation of the subcapsular renal hematoma. A repeat ultrasonography showed the complete resolution of the subcapsular renal hematoma with normal resistive index. During the following days, diuresis was back to normal and serial blood tests showed normal levels of creatinine. This case report highlights the importance of Ultrasonography in detecting subcapsular hematomas that could be a reversible cause of acute kidney injury and acute tubular necrosis in the setting of renal transplant.