A patient with biopsy documented acute poststreptococcal glomerulonephritis and arteritis recovered completely with supportive therapy. Illness was preceded by group A streptococcal pharyngitis. At the time of presentation, serum creatinine concentration was 11.5 mg/dl. Serum cryoglobulins containing IgG and C3 were present. The first biopsy, performed during the acute illness, contained glomeruli with typical features of acute PSGN. Medium-sized arteries had extensive necrosis and leukocytic infiltration, and contained IgG, C3, and fibrin. Glomerular filtration rate returned to normal within three weeks; proteinuria cleared by three months, and microscopic hematuria by 11 months. Renal biopsy one year later showed minimal mesangial hypercellularity and no arteritis.