Acute interstitial nephritis is characterized by renal inflammation and interstitial edema. The clinical presentation is pauci-symptomatic and often non-specific. Acute interstitial nephritis typically presents with acute renal failure, alone or with fever, eosinophilia, hematuria, sterile pyuria and small range proteinuria. An early diagnosis is crucial to prevent the morbidity and mortality associated with renal function decline. The most frequent etiology of this disease is drug-induced. A kidney biopsy is not systematically required to establish the diagnosis. It should be considered in the absence of renal function improvement 5 to 7 days after withdrawal of the causal agent. Although the benefits of glucocorticoid treatment have not been proven to date, its use may be associated with a better kidney function recovery.