Pseudomonas aeruginosa is a Gram negative bacilli frequently encountered in human pathology. This pathogen is involved in a large number of nosocomial infections and chronic diseases. Herein we investigated the effects of polyunsaturated fatty acids (PUFA) in chronic Pseudomonas aeruginosa lung infection. C57BL/6 mice were fed for 5 weeks with specifically designed diets with high contents in either 3, or 6 PUFA and compared to a control diet. P. aeruginosa included in agarose beads was then instilled intratracheally and the animals studied for 7 days. On the 4^th day, the mice fed with the 3 diet had a higher lean body mass gain and a lower 6/3 ratio of fatty acids extracted from the lung tissue compared to the other groups (p<0.05). The 3 group had the lowest mortality. Distal alveolar fluid clearance (DAFC) as well as the inflammatory response and the cellular recruitment were higher in the 3 group on the 4^th day. The effect on DAFC was independent of , ENaC, and Na, K-ATPase mRNA expressions, which were not altered by the different diets. In conclusion, a diet enriched in 3 PUFA can change lung membrane composition and improve survival in chronic pneumonia. This effect on survival is probably multifactorial involving the increased DAFC capacity as well as the optimization of the initial inflammatory response. This work suggests that a better control of the 6/3 PUFA balance may represent an interesting target in the prevention and/or control of P aeruginosa infection in patients.