Introduction. Retroperitoneal fibrosis is a rare cause of acute renal failure (ARF) with only a handful of cases reported in literature. We report a case of a 40-year-old male with an incidental finding of retroperitoneal fibrosis. Case Presentation. Patient is a 40-year-old African American male with no significant past medical history who presented with a four-month history of low back pain and associated nausea with vomiting. Physical examination was significant for elevated blood pressure at 169/107 mmhg and bilateral pedal edema. Significant admission laboratory include blood urea nitrogen (BUN) of 108 mg/dL, serum creatinine (Cr) of 23 mg/dL, bicarbonate of 19 mg/dL, and potassium of 6.2 mmL/L. Renal ultrasound showed bilateral hydronephrosis. Post-void residual urine volume was normal. Abdominopelvic CT scan showed retroperitoneal fibrosis confirmed with fine-needle biopsy. He was treated with a combination of bilateral ureteral stent placement, hemodialysis, and steroid therapy. Four months after hospital discharge, his BUN and Cr levels Improved to 18 mg/dL and 1.25 mg/dL, respectively. Conclusion. Retroperitoneal fibrosis should be considered as a differential diagnosis in patients with acute renal failure and obstructive uropathy. Abdominal CT scan is the examination of choice for diagnosis. Full resolution with treatment depends on the duration of obstruction.