Cystic Fibrosis (CF) is the most common lethal genetic disease in the Caucasian population and typically results in the development of bronchial inflammation, bronchiectasis, the progressive loss of lung function and ultimately death. Recently it has been shown that products of the Th(17) subset of T-cells, specifically, IL-17A and IL-17F are elevated in the sputum of CF patients. This review will go over experimental evidence supporting a role for the IL- 23/IL-17 axis in CF lung inflammation.