We retrospectively analyzed the long-term outcome of idiopathic pulmonary hemosiderosis (IPH) in 15 children. IPH started at a mean age of 5 years, and the mean duration of follow-up was 17.2 years (range, 10-36 yr). Four patients developed immune disorders, 3 cases of rheumatoid polyarthritis or rheumatoid polyarthritis-like diseases and 1 case of celiac disease. Respiratory outcome showed that 3 patients had severe symptoms: 2 patients developed severe pulmonary fibrosis resulting in major chronic respiratory insufficiency, and 1 patient had severe asthma. Twelve patients (80%) had mild or no respiratory problems and were able to lead a normal life. According to chest X-ray and pulmonary function test data, 4 patients had normal chest X-ray and no evidence of restrictive syndrome, 6 patients had an interstitial pattern on chest X-ray and evidence of restrictive pattern, 1 patient had an interstitial pattern but normal lung function, and 1 patient had a normal chest X-ray but evidence of mixed obstructive and restrictive pattern. Our results show that long-term survival is possible in patients with IPH. Factors of poor prognosis seem to be the presence of antineutrophil cytoplasm antibodies (ANCA) or other autoantibodies. No other clinical or biological predictive factors for prolonged survival were found.