A 47-year-old male was treated with chloramphenicol for a suspected lower urinary tract infection. Five days later, his urine output had dropped and was associated with a rapid rise in serum creatinine. A percutaneous renal biopsy showed evidence of acute interstitial nephritis. He was treated with low-dose steroids and his renal functions returned to normal within days. A causative association between acute interstitial nephritis and chloramphenicol is suggested.