Pseudomonas aeruginosa infects the airways of 80% of adults with Cystic Fibrosis (CF). In these patients, P. aeruginosa forms extremely antibiotic resistant biofilm communities that accelerate progression of obstructive lung disease. Current treatment of airway infection focuses on monthly cycles of inhaled antibiotics. However up to 20% of adults are infected with multi drug resistant P. aeruginosa for which we have no effective inhaled treatments. These isolates are more common as patients age so with the increasing life expectancy of the CF population, MDR P. aeruginosa is likely to remain a clinical problem. Another 10% of patients are infected with other Gram-negative organisms such as Burkholderia cepacia and Achromobacter species, for which we have inadequate suppressive treatment. Following lung transplant, MDR airway infections remain a problem as the allografts are colonized by strains carried in the paranasal sinuses. Sodium nitrite may present a new antimicrobial approach to treating respiratory infection with Gram-negative organisms, because it is able to prevent biotic biofilm formation.