Bioavailability of amoxicillin following a single intravenous and oral administrations as well as tissue residues were determined in broiler chickens. Effect of amprolium on the disposition kinetics and tissue residues of amoxicillin following repeated oral administrations was also investigated. Following a single intravenous injection of amoxicillin, 20 mg/kg.b.wt., in normal broiler chickens , plasma concentration-time curve was best described by a three - compartments open model with elimination half-life t0.5 = 9.78 ± 0.43 h, volume of distribution Vdss = 1012.06 ml/kg and total clearance of the drug CLtot =0.090 ml/kg/min. Following a single oral dosing, the maximum plasma concentration was 12.54 ± 0.140 g/ml, reached at Tmax =1.05 ± 0.042 h. The mean systemic bioavailability following oral administration was 67.33%. Following repeated oral administration in normal chickens, highest plasma concentration peaked after one hour of each oral dose. Amoxicillin showed accumulative behavior in plasma of broiler chickens. Amprolium resulted in a significant decrease in maximum plasma concentration of amoxicillin C max = 12.36 ± 0.506 g/ml compared with amoxicillin alone C max = 14.38 ± 0.373 g/ml. Amprolium resulted in a significant increase in total drug clearance Cltot = 1.43 ± 0.089 L/kg compared with amoxicillin alone (Cltot = 1.20 ± 0.028 L/kg). Amprolium resulted in a significant decrease in amoxicillin residues concentrations in all assayed tissues. It is concluded that the administration of amprolium before amoxicillin would altered its pharmacokinetic profile.