The disposition kinetics of levofloxacin was investigated in six male crossbred calves following single intravenous administration, at a dose of 4 mg/kg body weight, into the jugular vein subsequent to a single intramuscular injection of paracetamol (50 mg/kg). At 1 min after the injection of levofloxacin, the concentration of levofloxacin in plasma was 17.2 ¡¾ 0.36 ¥ìg/ml, which rapidly declined to 6.39 ¡¾ 0.16 ¥ìg/ml at 10 min. The drug level above the MIC₉₀ in plasma, was detected for up to 10 h. Levofloxacin was rapidly distributed from blood to the tissue compartment as evidenced by the high values of the distribution coefficient, ¥á (17.3 ¡¾ 1.65 /h) and the ratio of K₁₂/K₂₁ (1.83 ¡¾ 0.12). The values of AUC and Vd_area were 12.7 ¡¾ 0.12 ¥ìg.h/ml and 0.63 ¡¾ 0.01 l/kg. The high ratio of the AUC/ MIC (126.9 ¡¾ 1.18) obtained in this study indicated the excellent antibacterial activity of levofloxacin in calves. The elimination half-life, MRT and total body clearance were 1.38 ¡¾ 0.01 h, 1.88 ¡¾ 0.01 h and 0.32 ¡¾ 0.003 l/kg/h, respectively. Based on the pharmacokinetic parameters, an appropriate intravenous dosage regimen for levofloxacin would be 5 mg/kg repeated at 24 h intervals when prescribed with paracetamol in calves.