A high performance liquid chromatographic method (HPLC) was developed for the simultaneous determination of oxytetracycline (OTC), chlortetracycline (CTC), chloramphenicol (CP), sulfamonomethoxine (SMMX), sulfadimethoxine (SDMX), furazolidone (FZ) and difurazone (DFZ) in cultured fish. The drugs were extracted from fish with 0.5% metaphosphoric acid-methanol (8 : 2), and the extract was filtered and concentrated. The concentrated solution was passed through a Sep-pak C₁₈ cartridge. The cartridge was washed with water and eluted with methanol. The eluate was evaporated to dryness, and the residue was dissolved in acetonitrile-water (3 : 7). The sample solution was analysed by HPLC using a Nucleosil 5 C₁₈ column as a column and acetonitle 0.05 M monobasic sodium phosphate (35 : 65), pH 2.5 as a mobile phase. The average recoveries of OTC, CTC, CP, SMMX, SDMX and FZ from rainbow trouts, yellowtails and red sea breams fortified at 1.0 μg/g were 68.9-91.7%. The limits of detection were 0.05 μg/g for OTC, CP, SMMX, SDMX and FZ, 0.1 μg/g for CTC and 1.0 μg/g for DFZ.