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A simple and sensitive screening method using bioassay for the simultaneous analysis of antibacterials (penicillins, cephalosporins, macrolides, tetracyclines, aminoglycoside, quinolones, etc.) in meat has been developed. The drugs were extraced with 0.5% metaphospboric acid-methanol-acetonitrile (6: 2 :2), and the extracts were cleaned up on an OASIS HLB cartridge (200 mg). The pulp disk method with Bacillus subtilis ATCC 6633 (pH 6 and 8) and Micrococcus luteus ATCC 9341 (pH 8) as test organisms was employed for assaying the antibacterials. Many antibacterials, except for sulfa drugs, were detected with sufficient sensitivity (0.01 similar to 0.5 mu g/mL). The recoveries of typical antibacterials (penicillin G, ampicillin, cefapirin, cefalexin, erythromycin, spiramycin, oxytetracycline, chlortetracycline, streptomycin, dihydrostreptomycin, enrofloxacin and oxolinic acid) from swine muscle and liver fortified at levels of 0.05 similar to 0.5 mu g/g were 65 similar to 89%. Therefore, we recommend this proposed screening method for the routine analysis of residual antibacterials in livestock products.