A total number of 50 samples were collected from clinically diseased farm animals including diarrhea in calves, mastitis in cows, respiratory affections in sheep and abscess formation in sheep and goats at different localities in Alexandria Governorate to detect the prevalence of  Pseudomonas species. Pseudomonas aeruginosa was isolated from these samples at a  rate of 20 %, where the isolation from 10 samples of diarrhoeic calves, 12 mastitic milk of cows, 10 nasal swabs of sheep, 10 samples of pneumonic lung of sheep and 8 wounds and abscess swabs of sheep and goats were  at 10, 8.3, 20, 40, 25 % respectively. Moreover, 8 strains out of these positive strains gave positive hemolysin activity (B- Hemolysis) onto blood agar plates while experimental infection with isolated Pseudomonas aeruginosa revealed death of all embryos inoculated via yolk sac route. In vitro antimicrobial sensitivity results revealed that the isolated Pseudomonas aeruginosa were sensitive to Ofloxacine, Ciprofloxacin, Gentamycin but resistant to Nitrofuratoin, Amoxicillin, Cefotaxime, Amoxicillin calvulanic acid, Erythromycin, Trimethoprim. The antimicrobial activities of four different plant extracts (Ginger, Thyme, black seed, Cinnamon) which had antibacterial effects to some species of microorganisms were studied to the multi-drug resistant isolates of Pseudomonas aeruginosa in this research but they recorded no inhibition zones.