A total of fifty slaughtered chickens were collected from chicken shops in Giza governorate. All samples were examined for the presence of antibiotic residues using microbiological inhibitory assay (MIA). The freshly prepared Bacillus subtilis plates (pH 6 and pH 8) were used and incubated at 30ºC for 24 hrs. The results revealed that the incidence of antibiotic residues in the chicken carcasses was 22% and 20%, respectively. The residue levels of norfloxacin, using HPLC, after a single intramuscular injection of 2.5 mg/ kg body weight of norfloxacin for 5 successive days were not detected after 72 hours in muscle, gizzard, heart, skin and fat whereas, norfloxacin residues could not be detected after 96 and 120 hours in liver and kidney samples, respectively. Norfloxacin residues were decreased significantly (P<0.05) after heat treatments (boiling, roasting and frying) in muscles, liver and kidney samples. Such residues could not be detected after boiling, roasting or frying of gizzard, heart, skin and fat samples. The importance of antibiotic residues in chicken meat and the withdrawal time as well as the time of slaughter were discussed.