Wegener's granulomatosis was diagnosed in 2 boys, aged 17 and 16 years. The first presented with pain in the right flank, without coughing or dyspnoea. He did have peaks of fever, night sweats, weight loss, headache, and epistaxis. The second presented with progressive dyspnoea, haemoptysis, malaise, and headache. Because an infection was suspected, both were given antibiotics, but without effect. Chest X-rays revealed infiltrative abnormalities. A lung biopsy in the first patient and a nasal biopsy in the second revealed a granulomatous inflammation, and both patients had an elevated titre of antineutrophilic cytoplasmic antibodies (ANCA), with a cytoplasmic pattern, and an elevated result of the ELISA test for antiproteinase-3 (PR3). Both patients recovered after aggressive immunosuppressive treatment. Wegener's granulomatosis is a systemic necrotising vasculitis, mostly localised in airways and kidneys. The disease is very rare in children, but may be life-threatening. Therefore, in children with pulmonary problems resistant to antibiotics, it is important to consider a diagnosis of Wegener's granulomatosis and test for ANCA and PR3.