OBJECTIVE: To investigate the clinical characteristics of childhood antineutrophil cytoplasmic autoantibody (ANCA)-associated rapidly progressive glomerulonephritis. METHODS: The medical data, including clinical manifestations, laboratory findings, and kidney pathology, of 7 children with ANCA-associated rapidly progressive glomerulonephritis were retrospectively studied. RESULTS: The 7 patients (6 girls and 1 boy) ranged in age from 3.5-14 years, with a mean age of 9 years. A diversity of major complaints and clinical symptoms was presented in the patients. Laboratory findings were not specific. All patients had elevated ESR, BUN and serum creatinine levels as well as anaemia, hematuria and proteinuria. Urinary protein electrophoresis showed mixed proteinuria in the 7 cases. C3 was normal in 3 cases and slightly decreased in 4 cases. All were MPO-ANCA positive, and 1 out of the 7 cases was positive for PR3-ANCA. Renal biopsy displayed extensive crescentic formations and necrotic glomerulus capillary loop. A great quantity of inflammatory cell infiltration and swollen endotheliocytes of small vessels as well as vessel wall edema or necrosis were found in the interstitium. Immunofluorescence showed no or little amounts of immune complex depositions in the renal glomeruli and vessel walls. Renal function was recovered and hematuria/proteinuria disappeared or greatly relieved in 3 patients after methylprednisone and cyclophosphamide pulse therapy. CONCLUSIONS: Children with ANCA-positive rapidly progressive glomerulonephritis present with various clinical manifestations. The diagnosis of this disorder may be difficult due to a lack of specificity in its clinical manifestations. It is important to enhance our understanding of this disorder to effectively make an early diagnosis.