The current work aimed to study the phenotypic and genotypic characters of oxidase positive Gram negative bacterial pathogens recovered from different pathological lesions in broiler chickens. Samples were taken from 200 Hubbard and Ross broiler chickens of different ages (3-5weeks), from different farms in Beni-Suef and El-Fayoum Governorates during the period from January 2016 to April 2016. Bacteriological examination showed that Gram negative bacteria were 165 (82.5%) of isolates of which 60 isolates (30%) were oxidase negative while 105 isolates (52.5%) were oxidase positive including 43 Pseudomonas aeruginosa, 35 Aeromonas hydrophila, 12 Pasteurella gallicida, 10 Plesiomonas shigelloides, and 5 Vibrio vulnificus with incidences of 21.5%, 17.5%, 6% 5%, and 2.5%, respectively. The in-vitro sensitivity tests were applied on a total of 59 isolates; 20 P. aeruginosa, 19 A. hydrophila, 10 P. gallicida, 5 P. shigelloides and 5 V. vulnificus against 13 different antimicrobial agents and multidrug resistant isolates were detected. Multiplex-PCR was applied on 15 different MDR isolates. The results of PCR revealed that blaTEM, CIT and FOX genes were the most prevalent where they were found in 8 isolates (53.3%) followed by blaSHV which was found only in 5 isolates (33.3%)