Abstract BACKGROUND: Patients with severe Chronic Obstructive Pulmonary Disease (COPD) or Chronic Heart Failure (CHF) are often confronted with decisions concerning life-sustaining treatments. Aim of this prospective observational study was to assess life-sustaining treatment preferences, advance care planning and quality of end-of-life care communication in Dutch outpatients with clinically stable, but severe COPD or CHF. METHODS: The following outcomes were assessed in outpatients with severe COPD (n=105) or CHF (n=80): life-sustaining treatment preferences (cardiopulmonary resuscitation and mechanical ventilation; Willingness to Accept Life-sustaining Treatment instrument); advance care planning and quality of end-of-life care communication (Quality of Communication questionnaire). RESULTS: Most patients asserted in their current health status to prefer cardiopulmonary resuscitation (COPD: 70.5%; CHF: 62.5%) and/or mechanical ventilation (COPD: 70.5%; CHF: 66.3%). Patients' treatment preferences were influenced by burden of treatment, outcome of treatment and likelihood of outcome. Advance directives were discussed with the physician specialist by 5.9% of COPD patients and 3.9% of CHF patients. Patients rated quality of patient-physician end-of-life care communication as poor. Physicians scarcely discussed prognosis, dying and palliative care. CONCLUSIONS: Despite the fact that patients are able to indicate their preferences regarding life-sustaining treatments, based on burden of treatment, outcome of treatment and likelihood of outcome, these preferences are scarcely discussed with their physician specialist. This study shows a need for advance care planning, taking into account burden of treatment, outcome of treatment and likelihood of outcome in patients with severe COPD or CHF. Finally, quality of patient-physician end-of-life care communication needs to improve. NTR 1552 Dutch Trial Register.