Activation of the complement cascade plays an important role in the pathogenesis of postinfectious glomerulonephritis. We report successful terminal complement pathway blockade using an anti-C5 monoclonal antibody (eculizumab) in an 8-year-old child with severe acute postinfectious glomerulonephritis requiring hemodialysis. The child presented with clinical, serologic, and histopathologic criteria for diffuse crescentic postinfectious glomerulonephritis. Complement measurements showed low C3 and C4 levels, with increased SC5b-9 titers. The presence of a transient anti-factor H autoantibody was also identified. Eculizumab (600mg, 2 doses at a 1-week interval) was administered, with a striking recovery of kidney function. There were no additional hemodialysis sessions needed after the first dose of eculizumab, and glomerular filtration rate measured using inulin clearance at 12 months of follow-up was within the normal range (92mL/min/1.73m(2)). Prompt terminal complement blockade may have improved the outcome in this case of severe acute postinfectious glomerulonephritis.