The purpose of this study was to evaluate the pharmacokinetics of cefquinome (CFQ) following single intravenous (IV) or intramuscular (IM) injections of 2 mg/kg body weight in red-eared slider turtles. Plasma concentrations of CFQ were determined by high-performance liquid chromatography and analyzed using noncompartmental methods. The pharmacokinetic parameters following IV injection were as follows: elimination half-life (t1/2λz) 21.73 ± 4.95 hr, volume of distribution at steady-state (Vdss) 0.37 ± 0.11 L/kg, area under the plasma concentration–time curve (AUC0–∞) 163 ± 32 μg hr−1 ml−1, and total body clearance (ClT) 12.66 ± 2.51 ml hr−1 kg−1. The pharmacokinetic parameters after IM injection were as follows: peak plasma concentration (Cmax) 3.94 ± 0.84 μg/ml, time to peak concentration (Tmax) 3 hr, t1/2λz 26.90 ± 4.33 hr, and AUC0–∞ 145 ± 48 μg hr−1 ml−1. The bioavailability after IM injection was 88%. Data suggest that CFQ has a favorable pharmacokinetic profile with a long half-life and a high bioavailability in red-eared slider turtles. Further studies are needed to establish a multiple dosage regimen and evaluate clinical efficacy.