Background: Long-term oxygen treatment (LTOT) is very important, especially in patients with severe chronic obstructive pulmonary disease ( COPD), but its efficacy is closely related to patient compliance. Objectives: The aim of the present study was to investigate the compliance of patients under LTOT in the Prefecture of loan-nina ( north-western Greece) and to identify factors that might be involved. Methods: The study included 249 patients treated with LTOT during a 1-year period. They were visited at home by the investigating staff ( a chest specialist and a primary care nurse). Compliance to therapy was defined by the daily use of the O-2 concentrator ( in hours). Patients underwent pulse oximetry, basic spirometry, and trial inhalation of bronchodilators. Results: Only 67 patients (26.9%) complied with therapy, while the daily concentrator use lasted 9.7 +/- 6.09 h. SaO(2), FEV1 and FVC were negatively correlated to patient compliance. No significant differences concerning LTOT compliance were noted between men and women, urban and rural population, and between smokers, ex-smokers and non-smokers. A chest physician recommended LTOT for the majority of patients (86.3%), while COPD was the main reason for LTOT prescription (74.7%). Nevertheless, compliance to LTOT was not significantly higher when prescribed by a respiratory physician. No specific medical instructions and information was recorded for the majority of the study patients treated with LTOT. Conclusions: Our results suggest that an organized home care program establishing the relative guidelines is necessary for substantial improvement in patient compliance to LTOT in Greece. Copyright (C) 2004 S. Karger AG, Basel.