Long-term oxygen therapy (LTOT) improves survival in patients with chronic obstructive pulmonary disease (COPD) and severe hypoxemia. Adherence to LTOT guidelines is problematic, both because efficacy has been demonstrated only in specific groups of COPD patients, and because it implies high costs. Introduces treatment high costs. The aim of our study was to examine retrospectively the adherence to LTOT guidelines in a sample of medical records of patients prescribed LTOT between January 2005 and December 2006 in two Italian university hospitals (Ferrara and Modena). Out of a total of 191 medical records of patients prescribed LTOT, only 157 had adequate clinical data considering the three main criteria for appropriateness (arterial blood gas and/or pulse oximetry measurement, oxygen administration, smoking status). Out of these 157 patients, only 73 (46.5 %) fulfilled all three criteria recommended by the guidelines. Adherence was higher for LTOT prescribed by pulmonologists compared to internists. This survey showed that the adherence to LTOT guidelines in a sample of medical records of patients prescribed LTOT is poor. Considering the high costs and the impact on the patients' quality of life of LTOT, these results suggest that the adherence should be carefully monitored.