The pharmacokinetic properties of levofloxacin alone and with amprolium or toltrazuril were determined in broiler chickens after a single IV and oral administrations. After IV injection, levofloxacin serum concentration was best to be described by a two-compartment open model. Amprolium resulted in a significance increase in Vd_ss and Cl_tot (3.05 ± 0.17 and 0.65 ± 0.023 L/kg, respectively). In contrast, toltrazuril induced a significance decrease in Vd_ss and Cl_tot (1.71 ± 0.17 and 0.32 ± 0.015 L/kg, respectively) compared with levofloxacin alone (2.36 ± 0.34 and 0.44±0.009 L /kg, respectively). The elimination half-life and the mean residence time of levofloxacin were 4.07 ± 0.24 and 5.40 ± 0.26, 3.89 ± 0.24 and 4.77 ± 0.28, 4.10 ± 0.45 and 5.38 ± 0.36 h. in control, amprolium and toltrazuril respectively. Following oral dosing the maximum serum concentration was 3.27 ± 0.13, 2.17 ± 0.097 and 2.95 ± 0.11 µg/ml reached at 1.32 ± 0.096, 0.92 ± 0.057 and 1.30 ± 0.037h in control, amprolium and toltrazuril respectively. Amprolium and toltrazuril resulted in a significance decrease in interval between doses (19.10 ± 0.58 and 19.29 ± 0.51h respectively), compared with levofloxacin alone (27.39 ± 1.80 h.). Oral bioavailability was found to be 107.47 ± 9.23, 75.74 ± 4.50 and 53.51 ± 2.45% in control, amprolium and toltrazuril respectively. It was concluded that the pretreatment of (amprolium and toltrazuril) with levofloxacin altered the pharmacokinetic profile of levofloxacin.