A 46-year old patient under noramidopyrine treatment was admitted for acute renal failure. Renal biopsy was performed and showed acute interstitial nephritis without staining at immunofluorescent microscopy. In vitro and in vivo immunological tests using noramidopyrine as antigen were all negative. Abnormal serum creatinine levels were still present 4 months later. To our knowledge, noramidopyrine has rarely been the cause of interstitial nephritis (only one other case has been published), but it has frequently been responsible for drug-induced blood diseases, and noramidopyrine-related drugs have previously been involved in drug-induced nephritis. As the renal damage can probably be explained by a delayed hypersensitivity reaction, an early corticosteroid treatment would help in improving renal function.