A number of different vaccines and several monoclonal antibodies have been developed in the last decades for active and passive vaccination against the Gram-negative opportunistic pathogen Pseudomonas aeruginosa. These approaches include vaccine antigens such as lipopolysaccharide, surface polysaccharides, polysaccharide-protein conjugates, flagella, outer membrane proteins, pili, whole formalin-killed P. aeruginosa cells, live-attenuated P. aeruginosa and Salmonella enterica strains expressing P. aeruginosa antigens and DNA sequences. While many of these experimental vaccines and monoclonal antibodies have been tested in preclinical trials, only a few have reached clinical phases and none of these vaccines has obtained market authorization. The purpose of this review is to provide a brief summary of the present state of the development of vaccines and immunotherapies against P. aeruginosa infections. According to the different types of infection caused by P. aeruginosa--localized on mucosal surfaces such as the airways or systemic infection in the blood stream--several potential routes suggesting optimal means to administer the experimental vaccines are presented. Finally, the inherent problem of testing P. aeruginosa candidate vaccines in patient populations is discussed.