Chickens were used to investigate plasma disposition of chlortetracycline after single IV (15mg/kg) and multiple oral administration (60mg/kg, 5days) and residue depletion of chlortetracycline after multiple oral doses (60mg/kg, 5days). Plasma and tissue samples were analyzed by HPLC. Mean elimination half-lives in plasma were 7.96 and 13.15h after IV and multiple oral administration. Maximum plasma concentration was 4.33μg/ml and the interval from oral administration until maximal concentration was 1.79h. Oral bioavailability was 17.76%. After multiple oral dose, mean kidney, liver and muscle tissue concentrations of chlortetracycline+4-epi-chlortetracycline of 835.3, 192.7, and 126.3μg/kg, respectively, were measured 1day after administration of the final dose of chlortetracycline. Chlortetracycline residues were detected in kidney and liver (205.4 and 81.7μg/kg, respectively), but not in muscle, 3days after the end of chlortetracycline treatment. The mean chlortetracycline+4-epi-chlortetracycline concentrations were below LOQ at 3 and 5days after cessation of medication in muscle and liver, respectively. A withdrawal time of 3days was necessary to ensure that the chlortetracycline residues were less than the maximal residue limits (MRLs) established by the European Union (100, 300, and 600μg/kg in muscle, liver, and kidney, respectively).