Abstract: AIM　To study the pharmacokinetics and bioavailability of clinafloxacin in rats. METHODS　The drug concentration was determined by HPLC. The main pharmacokinetic parameters were obtained by 3P87 program. An RP-C₁₈ was used as the stationary phase. The mobile phase was a mixture of acetonitrile-0.05 mol·L^-1 citric acid triethylamine (pH 2.5) (20∶80). The flow rate was 1.0 mL·min^-1. The UV absorbance detector was set at 300 nm. RESULTS　A good linearity was obtained from 0.03-20 μg·mL^-1 of clinafloxacin in rat plasma with γ=0.9998. The plasma concentration-time curve of clinafloxacin conformed to one compartment open model. After ig administration of 50 mg·kg^-1and 100 mg·kg^-1 dose of clinafloxacin in six rats, mean C_max and AUC values increased in proportion to dose. Mean T_1/2 appeared to be independent of dose. Mean AUC was 65±6 and 27±4 μg·h·mL^-1 respectively after iv and ig adminostration of 100 mg·kg^-1 dose. The extent of bioavailability (F) of clinafloxacin was 42%. CONCLUSION　The results of the pharmacokinetic study of clinafloxacin showed that it exhibited first order kinetic characteristics and the bioavailability is low.