Although anemia frequently occurs in poststreptococcal acute glomerulonephritis (PSAGN), severe anemia is rare. We report severe normocytic, normochromic anemia (hematocrit, 19.8%) in PSAGN in a 6-year-old girl with edema, macrohematuria, and proteinuria for 1 month. The potential causes of severe anemia found in this case were: 1) longer duration of massive hematuria from onset of macrohemauria to treatment, 2) a level of erythropoietin much lower than that in cases of iron deficiency anemia, and 3) hemodilution. We speculate that these factors combined to cause an unusual case of severe anemia in PSAGN.