The pharmacokinetics of levamisole was studied in 20 broiler breeder chickens (chickens that give eggs to breed broilers). A single dose of levamisole (40 mg/kg) was administered orally or intravenously to chickens before the onset of egg production, prelay (age = 22 weeks), and repeated at the peak of egg production (age = 32 weeks). A high-pressure liquid chromatographic with ultraviolet detection method (HPLC-UV) was used for quantification of levamisole in plasma. Using compartmental analysis, levamisole followed a three-compartmental open model with mean values of α = 0.1224 and 0.4968, β = 0.01663 and 0.01813, γ = 0.002 and 0.002/min at the prelay and at the peak of egg production periods, respectively. The mean values for volume of distribution at steady state (Vss), determined by compartmental analysis, were significantly different for prelay and peak of egg production (8.358 and 13.581 mL/kg), respectively.