Pulmonary complications are by far the most serious complications in cystic fibrosis (CF). In response to endobronchial bacterial infections, the long-term consequences of chronically activated polymorphonuclear leukocytes (neutrophils) are thought to cause loss of lung function and premature death. Effective anti-inflammatory therapy implies that we understand the complex networks of the immune response with its myriads of mediators on effector cells. We have many steps to go in this context, but science has already shed some light on inflammatory mechanisms in CF airways, and anti-inflammatory treatment strategies have been applied clinically with some success. The aim of this chapter is to review our present knowledge, and we will focus on early inflammation, bacterial persistence mechanisms, neutrophil activation, cytokines and nitric oxide together with anti-inflammatory treatment strategies in CF patients.