AbstractIntroductionIvacaftor has shown to be effective in patients with cystic fibrosis (CF) with a G551D mutation.ObjectivesThis work aims to evaluate ivacaftor's effectiveness and safety in the real world, over 5 years, in the West of Scotland CF population.MethodsWe evaluated ivacaftor's effect on pulmonary function, body mass index (BMI), hospital bed occupancy, and adverse effects in patients ≥6 years with at least one G551D mutation.ResultsStatistically significant increases from baseline were observed in mean per cent predicted forced expiratory volume in 1 s (FEV1) at year 1 (which was maintained at years 2 and 5) and BMI over 5 years in our adolescent/adult cohort. Improvements were observed in per cent predicted FEV1within the paediatric cohort with a suggestion of a plateau effect. The increase in paediatric BMIz‐score was nonstatistically significant. There was a reduction in the number of pulmonary exacerbations requiring intravenous antibiotics and hospital bed occupancy. Ivacaftor was well tolerated.ConclusionIvacaftor was effective in our population.