Home mechanical ventilation (HMV) is used to treat chronic respiratory insufficiency in patients who are clinically stable and require partial or total support ventilation. To determine how HMV is being used in Spain, we mailed a questionnaire to the respiratory medicine departments of all hospitals in the public health system. The closing date for receipt of responses was April 1999. Forty-three hospitals in 14 autonomous communities of Spain responded. At the time of the survey, 1,821 patients were using HMV, which had been introduced in 1987. Volumetric respirations were being used by 856 patients and various models for delivering support pressure were being used by 965. Nasal masks connected to respirators were being used by 90%, while 6% were ventilated through a tracheotomy, 2% through face masks and fewer than 1% trough mouth devices. In conclusion, HMV has been widely applied in Spain and non invasive ventilation is usually provided through a face mask. HMV is prescribed for the usual reasons (chest and neuromuscular diseases) and for such conditions as hypoventilation due to obesity and chronic obstructive pulmonary disease.