We evaluated serum C-reactive protein (CRP) level and serum sodium concentration as early indicators of bacteremia in neutropenic children in two different series in 1983-1984 (49 bacteremias) and 1989-1990 (29 bacteremias). During the earlier period, the goal was to avoid unnecessary antimicrobial therapy. Currently a neutropenic patient is placed on antimicrobial therapy at the first sign of fever. In 1983-1984 the serum CRP concentration was elevated in every case, whereas in 1989-1990 it was normal in 34% cases (P = .0001). Hyponatremia was detected on admission in 84% and 52% cases (P = .0001). The urinary sodium concentration was elevated in most cases. The mortality in bacteremia was 22% in 1983-1984 compared to 3% (P = .025) in 1989-1990. Prompt initiation of empirical antimicrobial therapy in children with fever and neutropenia invalidates the use of hyponatremia and an elevated CRP level as early indicators of sepsis.