AbstractExperiences of anxiety and depression are common in adults with Cystic Fibrosis (AwCF) (e.g. Quittner in Thorax 69:1090-1097, 2014) and may impact on a wide range of important health-related behaviours, such as adherence to medication and timely attendance for medical review when experiencing pulmonary exacerbation. Common screening measures used in CF such as the PHQ-9 and GAD-7 may reflect an absence of anxiety or depression when clinically significant emotional difficulties are apparent on further assessment. This study preliminarily validated the previously developed Distress in Cystic Fibrosis Scale (DCFS) (Patel in Journal of Cystic Fibrosis 15:S26, 2016); a 23-item questionnaire to assess psychosocial distress in AwCF. Inpatient and outpatient participants with CF (N = 119) completed a battery of questionnaires, including the DCFS. PCA results supported a single component model. The DCFS showed high internal consistency and correlated significantly with measures of mood and quality of life. The DCFS shows promise as a screening tool to assess clinically significant psychosocial distress in an adult CF population.