The cell cytoskeleton (microtubules, microfilaments and intermediate filaments) plays an important role in many cell functions, such as maintenance of cell locomotion, movement and compartimentalization of intracellular organelles and cell-to-cell interaction. Therefore, cytoskeleton alterations may result in sever impairment of cell functions. The aim of this paper was to study the in vitro effects of Pseudomonas aeruginosa on the cytoskeleton of cultivated Hep-2 cells. Cytoskeleton modifications were evidenced by immunofluorescence using monoclonal and polyclonal antibodies against tubulin and vimentin, and rhodamine conjugated phalloidin, that specifically binds to actin microfilaments. We report here that P. aeruginosa has a strong cytopathic effect on monolayers within a few hours of contact with the cells, and influences the organization of microfilaments, but has no discernable effect on microtubules or intermediate filaments.