We describe a case of a 40-year-old lady diabetic and hypertensive, who presented with increasing fatigue and decreased physical endurance attributable to deterioration in renal function. The renal biopsy revealed drug-induced acute tubulointerstitial nephritis and the chronology of the events suggested the aetiology to be a recent intake of aceclofenac for knee pain. The patient improved with oral corticosteroids and the renal functions returned to baseline in 3 weeks. We did not come across a case of aceclofenac-induced acute tubulointerstitial nephritis on extensive electronic search of literature. This is probably the first case report of acute tubulointerstitial nephritis associated with the use of aceclofenac, a newer potent non-steroidal anti-inflammatory drug.