Pseudomonas aeruginosa is one of the major pathogens responsible for a wide variety of severe nosocomial and community acquired infections. Numerous vaccine candidates and several monoclonal antibodies have been developed over the past 40 years but only a few have reached clinical trials and none of these vaccine candidates has obtained market authorization. The understanding of P. aeruginosa pathogenesis and its virulence factors is essential in the identification of immunogens that can be used for a P. aeruginosa vaccine. This review summarizes the present status of vaccine development for this important pathogen.