This study investigated the prevalence, risk factors and rate of recognition of anxiety and depression in 50 patients hospitalized for exacerbation of chronic obstructive pulmonary disease (COPD). Using the Primary Care Evaluation of Mental Disorders questionnaire, 13 patients were identified as having depression, four had anxiety and eight had a combination of the two. Patients with anxiety and/or depression had a significantly higher partial pressure of oxygen and pH, and a lower partial pressure of carbon dioxide, in arterial blood on admission, more severe dyspnoea after a 6-min walk test and less improvement of dyspnoea from admission to discharge than COPD patients without anxiety and/or depression. Two patients were referred to a mental health specialist during their hospitalization, indicating a low rate of recognition. The results suggest that patients with mental disorders are referred and admitted to hospital earlier in the course of a COPD exacerbation due to earlier and more intense perception of dyspnoea.