Abstract: A liquid chromatographic (HPLC) method for determination of florfenicol in the plasma, muscle and liver of tilapia (Oreochromis niloticus O.aureus) was developed. For quantitation, the peak-height measurements and the internal standard were used. The study showed that the linearity and repeatability was good. The method was validated with blank samples fortified at 8, 1 and 0.125 gmL-1, the mean recovery was between 89.16% and 96.13%, the coefficient of variation was lower than 7.7%, and the detection limit for flofenicol was 0.03 gmL-1. All the results indicate its usefulness for conducting pharmacokinetics and residues studies on tilapia.