We report the case of an acute renal failure due to an acute interstitial nephropathy (ATIN) induced by non steroidal anti-inflammatory drugs (NSAID). Even though this pathology is a rare cause of acute renal failure, it still requires special attention in view of the fact that it induces a high risk of acute morbidity but it also can evolve into chronic renal failure. Its differential diagnosis with other causes of acute renal failure becomes essential because of the different therapeutic care. In this article, we are going to briefly sum up the reasoning to adopt in order to diagnose an acute renal failure.