Fourty samples of broiler chicken liver and muscles (twenty samples for each) were collected from popular markets of Benha city, Kaluobia governorate, Egypt to detect and analyze of Tilmicosin and Enrofloxacin residues using of High Performance Liquid Chromatography (HPLC), and also to detect their influence by heat processes. Tilmicosin residues were detected in all examined liver samples with a mean concentration of 481.88 ±54.81 ppb while Enrofloxacin residues were detected in only 66.66% of liver samples with a mean concentration of 8.288 ± 1.47 ppb while all examined muscle samples were free from any detectable levels. After boiling and using of autoclave, all residues of liver samples were undetectable. This study emphasized on the importance of strict analyzing of antimicrobial residues prior to marketing and also usefulness of heat cooking with or without pressure, for complete or partial elemination of antibiotic residues.