Cystic fibrosis (CF) is an autosomal recessive disorder resulting from two disease-causing mutations in the cystic fibrosis transmembrane regulator (CFTR) gene located on chromosome 7. CFTR is a chloride and bicarbonate channel found in sweat glands and the epithelial cells of the respiratory and digestive tracts. CF is the most common life-limiting genetic disorder in the UK, diagnosed in one in every 2,500 babies. The median age of death in the UK has been rising steadily and is 36 years. Most deaths in young people are the result of rapidly progressing lung disease. Use of CFTR modulators has resulted in a step change in CF management, improved lung function and will help to improve survival. CFTR modulator therapy targets the underlying CFTR defect.