Long-term home oxygen therapy (LTOT) improves survival of hypoxic patients with chronic respiratory insufficiency. However, the health-related quality of life (HRQL) of these patients, when LTOT is initiated, is severely impaired. The present study aims to describe the health-related quality of life (HRQL) of patients under LTOT, assessed at home, to identify parameters relevant to HRQL, and to describe changes over a 1-yr period. Seventy-nine patients (aged 68 +/- 11 years, under LTOT for 34 +/- 24 months) underwent pulmonary function testing, measurement of average daily distance walked, SaO2, dyspnoea scores (Borg scale and oxygen-cost diagram), and Hospital Anxiety and Depression scores. After 1 yr, measurements were repeated, and HRQL was measured with the St George Respiratory Questionnaire (SGRQ). Forced expiratory volume in 1 s (FEV1% of predicted) was 36 +/- 19; SaO2 (room air) was 87 +/- 5%, daily distance walked was 1202 +/- 1140 m; 21% suffered from anxiety and 27% from depression. After 1 yr, pulmonary function tests, dyspnoea or prevalence of anxiety or depression were unchanged. Mortality was high (31% 1-yr mortality). Daily distance walked (rho = -0.55, P = 0.01 vs. SGRQ) and number of days spent in hospital (rho = 0.5, P = 0.01 vs. SGRQ) were the parameters with the highest correlation with HRQL scores. Quality of life was poor in these patients, with high rates of emotional disorders. Restoring and maintaining sufficient exercise capacity for everyday life activities through outpatient rehabilitation programmes and support for emotional disturbances should be major goals in the care of these patients.