Although sleep problems have an important impact on daily life and health outcome measures in patients with chronic obstructive pulmonary disease (COPD), patterns of sleep disturbance in patients with mild-moderate COPD remain unknown.The aim of this study was to investigate patterns of sleep disturbance and factors associated with sleep impairment in patients with mild-moderate COPD.This prospective cross-sectional study enrolled 148 male patients with COPD. At enrolment, all patients completed a disease-specific sleep measure, the COPD and Asthma Sleep Impact Scale (CASIS) to assess sleep impairment. Health-related quality of life (HRQL) was measured using the St. George's Respiratory Questionnaire (SGRQ) and the 36-item Short-Form health survey (SF-36). Anxiety and depression status were assessed using the Hospital Anxiety and Depression Scale (HADS). Self-efficacy was measured by the COPD self-efficacy scale (CSES).The mean age of the subjects was 67 years [standard deviation (SD) = 8.11]. The proportion of patients who indicated that they had a bad night's sleep was 33.1%. Univariated analysis showed that CASIS score was significantly correlated with the modified Medical Research Council (mMRC) dyspnea scale, SGRQ, SF-36 Physical Component Summary (PCS), SF-36 Mental Component Summary (MCS), HADS-anxiety, HADS-depression and CSES scores (all p < 0.05). In a multivariate analysis, SGRQ and CSES were independently associated with CASIS score.Poorer HRQL and lower self-efficacy are significantly associated with sleep disturbance, and perhaps may be improved by better sleep quality. Future research is required to enhance sleep quality in patients with mild-moderate COPD. This article is protected by copyright. All rights reserved.