To describe the clinical and laboratory characteristics of patients on long-term home oxygen therapy followed up by the home care program of Hospital das Clínicas, School of Medicine, Universidade de São Paulo, during a period of 8 years; to compare groups with and without secondary pulmonary hypertension; and to estimate the cost of the program using oxygen concentrators vs. oxygen cylinders provided by the hospital. A descriptive, retrospective cohort study of patients on long-term home oxygen therapy followed up from 2002 to 2009 at the Unit of Pulmonology, Children's Institute, Hospital das Clínicas, School of Medicine, Universidade de São Paulo. We studied 165 patients, of whom 53% were male, with the following medians: age at the beginning of oxygen therapy--3.6 years; duration of oxygen therapy--7 years; and survival time after beginning of oxygen therapy--3.4 years. The main diagnoses were: cystic fibrosis (22%), bronchopulmonary dysplasia (19%), and bronchiolitis obliterans (15%). Of the 33 patients who underwent spirometry, 70% had severe obstructive lung disease. Echocardiogram was performed in 134 patients; 51% of them had secondary pulmonary hypertension. There was a statistically significant association between pulmonary hypertension and need of higher oxygen flows (chi-square, p = 0.011), and between pulmonary hypertension and longer duration of oxygen therapy (Logrank, p = 0.0001). There was no statistically significant difference between survival time after the beginning of oxygen therapy and pulmonary hypertension. The average monthly costs of the program were US$ 7,392.93 for concentrators and US$ 16,630.92 for cylinders. Long-term home oxygen therapy was used to treat different chronic diseases, predominantly in infants and preschool children. There was a high frequency of pulmonary hypertension associated with longer periods of oxygen use and greater oxygen flow, without association with survival rate. The use of concentrators instead of cylinders may reduce costs significantly.