Aim.To evaluate the diagnostic utility of computed tomography (CT) obtained during prolonged febrile neutropenia in pediatric oncology patients.Methods.We evaluated the medical records of all patients with a malignant disease who had a CT examination during an episode of febrile neutropenia lasting for 4 days or more at Children’s Hospital and Regional Medical Center in Seattle, WA, between January 1, 1997, and June 1, 1999.Results.CT was performed on 83 patients to evaluate 109 episodes of prolonged febrile neutropenia. Sixty-eight (62%) of the initial CT scans demonstrated abnormalities, leading to changes in therapy in 42 (39%). The diagnostic and therapeutic utility of CT varied by anatomic site. Abdominal and head/neck CT detected abnormalities in only 19 and 8% of studies, respectively, resulting in therapy changes in 9 and 4%, respectively. Sinus CT demonstrated abnormalities in 41% of cases and altered therapy in 24%. Chest CT had the highest diagnostic utility, with 49% of cases demonstrating abnormalities, leading to therapy alteration in 30%. CT was rarely abnormal in the absence of localizing signs or symptoms. In 55 instances 1 or more follow-up scans were done. Thirteen follow-up CT scans showed abnormalities that led to a change in therapy.Conclusions.CT-detected abnormalities frequently lead to alterations in therapy, particularly sinus and thoracic CT. Most patients with CT-detected abnormalities have symptoms or signs referable to the site of abnormality. Asymptomatic febrile neutropenic children rarely have CT findings that lead to a change in therapy.