Acute tubulo-interstitial nephritis (ATIN) is an important cause of acute renal failure resulting from a variety of insults, including immune complex-mediated tubulo-interstitial injury, but drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) are a far more frequent cause. Overall, as an entity, ATIN remains under-diagnosed, as symptoms resolve spontaneously if the medication is stopped. We report on a 14-year-old boy who developed acute renal failure 2 weeks after aortic valve surgery. He was put on aspirin following surgery and took ibuprofen for fever for nearly a week prior to presentation. He then presented to the emergency department feeling quite ill and was found to have a blood urea nitrogen (BUN) concentration of of 147 mg/dl, creatinine of 15.3 mg/dl and serum potassium of 8.7 mEq/l. Dialysis was immediately initiated. A kidney biopsy showed inflammatory infiltrate consistent with ATIN. However, in the tubular basement membrane (TBM), very intense granular deposits of polyclonal IgG and C3 were noted. He needed dialysis for 2 weeks and was treated successfully with steroids for 6 months. His renal recovery and disappearance of proteinuria took a year. In conclusion, this is a first report of NSAIDs-associated ATIN, showing deposits of granular immune complex present only in the TBM and not in the glomeruli.