Klebsiella pneumoniae is a common environmental pathogen which causes mastitis in dairycows and is usually treated with antibiotics, thereby potentially increasing antimicrobialresistance. In the present study, 200 milk samples were collected from 160 mastitic cows, inaddition to 40 apparently normal milk samples from in cows contact with mastitic ones as
well as environmental samples (n = 44) from private dairy farms in Giza suffering from problems of mastitis and a decrease in milk production. Bacteriological examination revealed that Klebsiella pneumoniae was predominant in an incidence of (84.5%), E. coli (12.6%) and Pseudomonas aeruginosa (2.9%). All Klebsiella pneumoniae isolates were subjected to disc diffusion sensitivity tests and all were resistant to Amikacin, Amoxicillin/Clavulanic Acid, Pencillin, and Tetracycline (100%),
followed by Ampicillin (96.6%), Erythromycin, Tobramycin (86.2%) and Chloramphenicol (81.6%). The highest sensitivity was to Kanamycin (100%) and Neomycin (97.7%). Virulence and antibiotic resistant genes of Klebsiella pneumoniae were detected by PCR and all the tested six isolates of Klebsiella pneumoniae were positive for fimH, and kfu in virulence genes but magA was detected in five isolates. Also antibiotic resistant genes bla TEM and tetA were detected in all isolates by PCR.