Accurately, ninty samples of meat, liver and kidneys were collected from abattoirs from different places in Qalyobia and Gharbia governorates for detection of their oxytetracycline residues by using HPLC and various cooking methods (boiling, frying and grilling) were applied on beef and offal for detection and study the effect of heat treatment on such antibiotic residue levels. The obtained results indicated that oxytetracycline residues were detected in 23.33%, 33.33% and 40% of the examined samples of beef, liver and kidneys, respectively and the level of OTC residues (µg/kg) in the examined samples of meat, liver and kidneys ranged from 26.8 to 346.5 with mean value of 151.79 ± 11.64, from 58.1 to 1921.4 with mean value of 822.56 ± 37.36 and from 72.3 to 3118.9 with mean value of 1457 ± 42.81, respectively. Accurately, 90%, 80% and 76.67% of examined samples of beef, liver and kidneys, respectively were accepted. This accordance to MRL of OTC (200µg/kg for meat , 600 µg/kg for liver and 1200 µg/kg for kidneys) which stipulated by US code of federal regulations (2003), FAO/WHO (2004), Egyptian Organization of Standardization and Quality Control “EOSQC" No. 3692 (2008). The effect of different cooking methods (boiling, frying and grilling) on oxytetracycline (OTC) residues in beef and offal samples revealed that before boiling, frying and grilling the concentration of OTC residues in cattle meat were 26.8 ug/kg, 195.2 ug/kg and 346.5 ug/kg.  After boiling, the concentrations of OTC residues were 0 ug/kg, 12.4 ug/kg and 198.9 ug/kg and the reduction % was 100%, 93.7%and 42.6%, respectively.  After frying, the concentrations of OTC residues were 0 ug/kg, 0 ug/kg and 57.1 ug/kg and the reduction % was 100%, 100% and 83.5%, respectively. After grilling, the concentration of OTC residues were 0, 0 and 26.8 ug/kg and reduction% was 100%, 100% and 92.3%, respectively.