Background: Anxiety and depression are mental health problems that result in reduced health-related quality of life (HRQL), and increased mortality. Patients with COPD have a higher risk of anxiety and depression compared to healthy individuals. Recent studies reported a significant relationship between the presence of anxiety and depression and the functional status of COPD patients.Objectives: To study the effect of treatment of anxiety and depression on the physiological status in COPD patients.Materials and methods: The study included 50 severe COPD patients with depression and/or anxiety as evaluated and scored by Montgomery and Asberg Depression Rating Scale (MADRS) and Hamilton Anxiety Rating (HAM-A) Scale. They were classified into 2 groups: group I included 25 patients who received antidepressant/anxiolytic therapy in addition to COPD treatment and group II included 25 patients who received COPD treatment only. Modified Borg scale dyspnea score, spirometry (vital capacity, forced vital capacity, forced expiratory volume in first second and forced expiratory flow through 25-75% of expiration), arterial blood, MADRS and HAM-A scale were assessed in all patients at the start of the study and after 3 months.Results: Patients with severe COPD who were treated for depression and/or anxiety showed a significant improvement in MADRS, HAM-A and dyspnea scales, spirometeric parameters and oxygenation. MADRS and HAM-A scale showed a significant negative correlation to FEV1.