The importance of infection in the pathogenesis of cystic fibrosis (CF) lung disease has been long recognized, and the use of antibiotics targeting bacteria identified in cultures of respiratory specimens has played a critical role in improving outcomes for individuals with CF. Over the past ∼15 years, the use of culture‐independent methods to assess airway microbiology in CF has revealed complex and dynamic CF airway bacterial communities. Recent areas of investigation of the CF lung microbiome have included exploring how bacterial community structures change over time, particularly with respect to disease progression or pulmonary exacerbation, and in response to antibiotic therapies. This review will discuss what has been learned from these studies as well as how these findings offer opportunities to further refine management of CF airway infection. Pediatr Pulmonol. 2015; 50:S31–S38. © 2015 Wiley Periodicals, Inc.