OBJECTIVES: Febrile neutropenia (FN) is a common side effect of cancer chemotherapy that considerably increases the total cost of management. Standard clinical practice of treating FN consists of either immediate hospitalization or ambulatory treatment depending on the patient’s risk of complications and co-morbidities as evaluated by the MASCC score (Multinational Association for Supportive Care in Cancer). The objective of this study was to evaluate the budgetary impact of in-patient management of patients with FN. METHODS: The study prospectively included 102 consecutive patients with a solid tumor admitted with FN to the emergency department of Institut Gustave Roussy between March and October 2006. Patients were treated according to standard clinical practice. Costs were analyzed from the hospital perspective. The cost of each stay was extracted from the hospital cost accounting system and compared to the reimbursement tariff received from Diagnosis Related Group (DRG). The observed length of hospital stay was also compared with the mean length of stay in the DRG. RESULTS: Mean (SD) patient age was 50.7 ± 14.7 years and 68 patients (66.6%) were women. For all patients, FN followed the administration of chemotherapy. Fourteen (13.7%) patients were treated on an out-patient basis and were excluded from this analysis. The mean length of stay of the 88 in-patients was estimated to be 6.2 ± 7.2 days. The mean cost per stay was estimated to be €6096 (median: €3796), whereas the mean tariff reimbursement was €5125 (median: €4319). CONCLUSIONS: On average, the management of in-patients with FN is in deficit by €971 per stay at Institut Gustave Roussy. Five specific patient stays were largely responsible for the global deficit, as in these cases, the duration of hospitalisation was longer than that specified in the DRG.