Health-related quality of life is a potentially important marker for evaluating existing and new therapies in bronchiectasis. The Leicester Cough Questionnaire (LCQ) is a symptom specific questionnaire designed to assess the impact of cough severity, a major symptom of bronchiectasis. This study aimed to validate the LCQ in bronchiectasis. The validity, responsiveness and reliability of the LCQ were assessed as follows: ability to discriminate severe and mild disease; change in score following antibiotic treatment for exacerbations; repeatability over a 6-month period in stable disease; and comparison with the St George's Respiratory Questionnaire (SGRQ). In total, 120 patients (51 with severe disease, 29 with moderate disease and 40 with mild disease) completed the LCQ and SGRQ. The area under the receiver-operator curve was good for both severe and mild disease (0.84 and 0.80 respectively, p<0.0001). Following 2 weeks' antibiotic treatment, the median LCQ score (interquartile range) improved from 11.3 (9.3-13.7) to 17.8 (15-18.8) (p<0.0001). The LCQ score was repeatable over 6 months in stable disease (intraclass correlation coefficient of 0.96 (95%CI 0.93-0.97), p<0.0001). Correlation between the LCQ and SGRQ scores was -0.7 in both stable disease and exacerbations (p<0.0001). The LCQ can discriminate disease severity, is responsive to change and is reliable for use in non-cystic fibrosis bronchiectasis.