To describe the users of home mechanical ventilation treatment in Iceland.Records for all patients in Iceland using noninvasive ventilatory support at home on April 30th 1999 were analysed.A total of 54 patients were using ventilatory support at home. There were 33 males and 21 females. The mean age for the group was 61 years. The mean treatment time was 3.5 years. The majority were using pressure controlled ventilators that were connected to a nose mask or full face mask. The most common reason for treatment was decreased respiratory muscle function. In 11 patients this was secondary to muscle- or neurological diseases, in nine from TBC sequelae and in six post polio or from idiopathic kyphoscoliosis. In addition there were 21 patients that had a combination of chronic obstructive pulmonary disease and sleep-related breathing disorder. Cheyne-Stoke breathing secondary to congestive heart failure was the reason for home ventilatory treatment in five males and two females. These patients had relatively normal spirometric and bloodgas results, which is in contrast to the rest of the group, where spirometric values were on the average less than 50% of predicted. Arterial blood gases commonly showed hypoxia and 16 of the patients had long-term oxygen therapy (over 16 hrs/day).Home ventilatory treatment has become part of medical treatment in Iceland and benefits patients with decreased ventilatory function, especially during sleep.