The purposes of this study were to evaluate the distribution of quinolone and to investigate the effects of quinolones (enrofloxacin, ciprofloxacin) in blood(plasma) and eggs of laying hens. Animals were fed quinolones which supplemented with 20, 50, 80 mg/kg of body weight. Blood and egg samples were collected after oral administration and analyzed for quinolones (enrofloxacin, ciprofloxacin) by HPLC. In laying hens, the residue period of enrofloxacin were longer than that of ciprofloxacin and the levels of residues were elavated by drug dosage.