We report the findings of a 46-year-old man, who presented with fever and renal dysfunction while undergoing treatment for Crohn's disease with infliximab (IFX). Remittent fever and renal dysfunction with urinary casts developed and lasted for 3 weeks without deterioration of Crohn's disease. Renal biopsy revealed acute tubulointerstitial nephritis (ATIN). After the discontinuation of IFX, his fever and renal abnormalities resolved. We herein report the first known case of ATIN associated with IFX.