Wegener's granulomatosis is a form of systemic vasculitis of unknown etiology that affects the small blood vessels. The disease is characterized by the formation of granulomas on small and medium blood vessels, and often affects the respiratory tract and renal system. In 86% of diagnosed cases, renal compromise is in the form of glomerulonephritis. Wegener's granulomatosis can occur at any age, principally during the 4th and 5th decades of life, and 85% of cases occur over the age of 19 years. In the United States about 3 per 100,000 cases are reported, with a major occurrence in males. The present report is about a case of a 12 year old female with Wegener's granulomatosis of 18 months of evolution, with symptoms such as epistaxis, generalized edema, cough, dyspnea, hemoptysis, high blood pressure and macroscopic hematuria. Out of the five criteria for the diagnosis of Wegener's granulomatosis, she had perinuclear anti-neutrophil cytoplasmic antibody positive to serum p-ANCA mark, which is the least frequent, which makes more difficult the diagnosis. Over a period of five years, in our hospital, we have diagnosed 11 patients with Wegener's granulomatosis, and the present case is the only pediatric case.