OBJECTIVES: In COPD, disturbed sleep is related to exacerbation frequency, poor quality of life and early mortality. We developed the Manchester Sleep Symptoms Index (MSSI) to assess night-time symptoms and disturbed sleep in COPD. METHODS: Identification of potential items was guided by interviews and focus groups involving COPD patients and age-matched controls. Hierarchical methods and Rasch analysis informed item deletion and development of a unidimensional scale. Internal consistency and test-retest reliability were assessed. Concurrent validity was examined using Pearson’s correlation with the St George’s Respiratory Questionnaire (SGRQ), modified MRC Dyspnoea Scale, FACIT fatigue scale, MOS Sleep Scale, HADS Anxiety and Depression scores. RESULTS: Qualitative data from 36 patients with COPD and 10 age-matched controls informed an initial list of 22 items. The cross-sectional study included 203 COPD patients (GOLD: I:14% II:41% III:25% IV: 7%; male: 63%, mean age: 64.7; SD: 7.5 years) and 50 non-COPD controls. 12 items were removed during hierarchical methods and a further two following Rasch analysis. The final MSSI contains 8 sleep-related items that are specific to COPD patients: breathlessness, chest tightness, cough and sputum production. The index has good internal consistency (Cronbach’s alpha 0.87), test-retest repeatability (intra-class coefficient 0.77) and validity. Total MSSI scores significantly correlated with the SGRQ (r=0.64); MRC Dyspnoea scale (r=0.46), FACIT-F (r=-0.61); MOS problems index 2: (r=0.62); MOS Sleep adequacy (r=0.40); MOS Sleep disturbance (r=0.53) HADS anxiety (r=0.54) and depression (0.48).  There was good overall fit to the Rasch model (Chi-squared: 29.2 df: 16 p=003.) and distribution of item scores. CONCLUSIONS: The MSSI is a reliable, valid, uni-dimensional self-reported outcome measure of sleep and night-time symptoms for people with COPD. It is simple and quick to use making it suitable for research and practice. Further work is needed to determine the minimal clinical important difference and cross cultural validity.