Pseudomonas species were used in bioremediation technologies. In situ conditions, such as marine salinity, could limit the degradation of hydrocarbons and aromatic compounds by the bacteria. Biofilm ability to tolerate environmental stress could be used to increase biorestoration. In this report, we used scanning confocal laser microscopy and microtiter dish assay to analyse the impact of hyperosmotic stress on biofilm formation by Pseudomonas aeruginosa. We used benzoate as the sole carbon source and the effect of the stress on its degradation was also studied. Hyperosmotic shock inhibited the biofilm development and decreased the degradation of benzoate. The osmoprotectant glycine betaine partially restored both the biofilm formation and benzoate degradation, suggesting that it could be used as a complement in bioremediation processes.