Fifty Low apparently healthy one day old. At fourth week of age chicks were used in this study injected lnlramluscularly with norfloxacin at a dose of 5 mg/ Kg body weight for 5 successive days for detection of norfloxacin residues, eight broilers were slaughtered on (1 st, 3rd, 5th , 7th and 9th day) after last dose. Muscles (breast, thigh)fal. liver and gizzard were examined before and after boiling (100 c for 30 minules) for determination of norfloxacln residues and studying effect qf heat trealment on its persistence. and samples from muscles (breast. thigh) liver and gizzard of 12 broilers were examined before and after freezing at -180 C weekly Jor quantitative determination of norfloxacin residues using HPLC. The resulls showed that narfloxacin highest conecentration level was deiected in breast muscle at 1st day from Last dose (39.21 ± 3.012 ug/g) and decreased till not detected at 9th day followed by liver (27.23 ± 2.321 ug/g) andJa/ 25.15 ± 1.951 ug/g) and its level was showed significant decrease at (P 0: 0.05)till not detected at 9th day. Lowesl concentration level showed in Gizzard and thigh (17,32.± 1.6J 5 and 12.S ± 1.033 ug/g) and not detected at 7th day.