We investigated the effects of hepatic and renal impairment on the pharmacokinetics of enrofloxacin in Sprague-Dawley rats. Experimental hepatic and renal failure were induced by carbon tetrachloride (CCL4) and 5/6 nephrectomy, respectively. After intravenous dosing of enrofloxacin (10 mg/kg), plasma concentrations of enrofloxacin were measured using liquid chromatograph/mass spectrometry. There was no significant effect of hepatic impairment on enrofloxacin pharmacokinetics. However, renal impairment markedly prolonged elimination half life (t1/2λz) of enrofloxacin (P<0.05), comparing with respective control. Total body clearance (Clb) and volume of distribution at steady state (Vss) were significantly decreased (P<0.05) by renal impairment. In conclusion, these results suggested that renal impairment could affect the pharmacokinetics of enrofloxacin.