A 3-month-old male kitten was presented to our clinic with malaise, vomiting and jaundice. In the anamnesis, we learned that the cat had a history of anorexia, sneezing, and nasal discharge and that the owner had administered 100 mg/day (t.i.d.) nimesulide orally for three days. In the laboratory study, high levels of serum alkaline phosphatase, gamma-glutamyl transtransferase, total bilirubin, direct bilirubin, indirect bilirubin, urea, and creatinine were detected. All the clinical signs and laboratory abnormalities returned to normal levels after cessation of the nimesulide and supportive treatment. In this case, clinical and laboratory findings were thought to be compatible with nimesulide-induced acute biliary injury and renal failure. This case report indicates that the household pets are at risk of toxic drugs administered by their owners and great caution should be taken in administering NSAIDs in cats.