Pseudomonas aeruginosa vaccine (PV) containing cell proteins with molecular weight (Mr) 20,000-100,000 and up to 0.08% (w/v) admixture of lipopolysaccharide was obtained by water-salt extraction and subsequent ultrafiltration. PV protects mice against experimental P. aeruginosa infection, stimulates production of specific protective antibodies in rabbit and does not provoke obvious toxicity in laboratory animals.