A total of 200 samples of raw and pasteurized milk (100 of each) were collected from supermarkets in Qaluobia Governorate and examined for prevalence and characterization of P. aeruginosa .The incidence of P.aeruginosa isolated from raw and pasteurized milk was 40 %and 16%, respectively. Serogrouping of P.aeruginosa isolated from examined samples revealed that serogroupes K, H and, A isolated from raw milk at frequency percentage of 40, 35, and 25, respectively, while from pasteurized milk at frequency percentage of 25, 50 and 25, respectively. For the detection of the enzyme Hameolysine, Phospholipase, Caseinase and Gelatinase revaled that for serogroupe K it were 60,50,100 and 90 % respectively while for serogroupe H it were 54.5,45.5,100 and 81.8 % respectively and it were 42.8,28.5,100and85.7% for serogroupe A, respectively. Concerining the pathogenicity test of P.aeruginosa isolated from milk samples it was in percent 100, 100  and 57.14 for serogroupes K, H and A, respectively. P.aeruginosa varied in its resistance to different antibacterial agents, ciprofloxacin was the most effective drug against P.aeruginosa (60.7%), followed by enrofloxacin, norfloxacin and lomefloxacin (53.6%). P.aeruginosa was low in susceptibility to tobromycin (25.0%), gentamycin (21.4%) ceftriaxone (17.9%) streptomycin (10.7%) erythromycin (3.6%) tetracycline (3.6%). The organism was completely resistant to trimethoprim, naldixic acid and doxycen. For identification of P. aeruginosa strains at the DNA level, Polymerase chain reaction (PCR) is used based on specific primer for 16S rRNA, PCR has found to be rapid and more sensitive and specific in identification of P. aeruginosa, and the bands appeared at 956 bp.