Fifty episodes of febrile neutropenia (FN) in 33 children with malignancies were studied to evaluate the usefulness of C-reactive protein (CRP) levels as an indicator of infection, and the efficacy of antibiotic therapy. Nineteen FN episodes occurred in children with documented infection whereas, 9 and 22 episodes occurred with probable infection and fever of unknown origin, respectively. CRP positivity during episodes of documented and probable infection was significantly higher than with febrile episodes of unknown origin. Blood culture was positive in 15 episodes; of these, CRP was positive in 11. CRP declined to normal on 7th day of antibiotic therapy. CRP is a useful indicator of infection in neutropenic children and also in determining the efficacy of antibiotic therapy.