Pseudomonas aeruginosa pneumonia is a life threatening complication in mechanically ventilated patients that requires the ability of the bacteria to adhere to, and colonize the endotracheal intubation device. New strategies to prevent or reduce these nosocomial infections are greatly needed. We report here the study of a set of P. aeruginosa clinical isolates, together with specific mutants, regarding their adhesion on native and chemically modified poly(vinyl chloride) (PVC) surfaces from endotracheal intubation devices. The adhesion of the different strains to untreated PVC varied widely, correlating with several physico-chemical characteristics known to influence the attachment of bacteria to inert surfaces. The adhesion patterns were compared to the calculations obtained with the DLVO theory of colloidal stability. These results illustrate the importance of testing different clinical isolates when investigating bacterial adhesion. Oxygen plasma treatment of the PVC pieces yielded a hydrophilic surface and reduced the number of adhering bacteria by as much as 70%. This reduction is however unlikely to be sufficient to prevent P. aeruginosa colonization of endotracheal intubation devices.