The minimal inhibitory concentrations(MICs) of enrofloxacin, danofloxacin and difloxacin for Pasteurella multocida were determined by two fold dilution method in vitro . The inhibitory tests in vitro showed that the MICs of enrofloxacin, danofloxacin and difloxacin was 0.05 , 0.2 and 0.4 mg/L for Pasteurella multocida , respectively. Treatment trials on chickens with experimentally induced fowl cholera were carried out with enrofloxacin, danofloxacin and difloxacin at dosage rate of 5 mg/kg by oral administration twice daily for 3 successive days. Following the treatment with enrofloxacin, danofloxacin and difloxacin (po, 5 mg/kg) against fowl cholera for 3 days, the curative rates of the drugs for Pasteurella multocida infected chickens were 96 7%, 83 3% and 83 3%, respectively. In the Pasteurella multocida infected and untreated groups, mortality of the chickens was 100%. There were no significant difference in weight gains among the three groups given the above drugs.