Chronic infectious rhinosinusitis with Pseudomonas aeruginosa is common in cystic fibrosis and may result in allograft infection after lung transplantation. Sinus surgery followed by nasal care may reduce these adverse effects. Sinus surgery was performed in 37 patients with cystic fibrosis after transplantation. Bacteriology of sinus aspirates (n=771) and bronchoalveolar lavage (BAL) (n=256) was correlated with clinical data. Sinus surgery was successful in 54% and partially successful in 27% of patients. A significant correlation between negative sinus aspirates and negative BAL and between positive sinus aspirates and positive BAL (P<0.0001) was found. Successful sinus management led to a lower incidence of tracheobronchitis and pneumonia (P=0.009) and a trend toward a lower incidence of bronchiolitis obliterans syndrome (P=0.23). Sinus surgery followed by daily nasal douching may control posttransplant lower airway colonization and infection. In the long term, this concept may lead to less bronchiolitis obliterans syndrome by decreasing bronchiolar inflammation.