OBJECTIVES: Febrile neutropenia (FN) is a potentially life-threatening complication of chemotherapy which generally prompts immediate hospitalisation.  The study objective was to evaluate the resource use and cost of hospitalisation for FN within the Irish Healthcare setting.  Micro-costing techniques were used. The health payer perspective was adopted.  METHODS: This was a single centre study.  Adult cancer patients undergoing chemotherapy, who were subsequently admitted for FN, were identified prospectively.  Patient medical records were reviewed retrospectively.  RESULTS: Patient demographics and resource utilisation data (pertaining to the management of FN) were obtained from a cohort of 32 patients (69% female, mean age = 58.8 years).  Twenty-five percent of patients had more than one FN episode.  In total, 42 FN episodes were captured; 60% of episodes had occurred within the first two cycles of chemotherapy. The bootstrap estimation was used to determine mean hospital length of stay (LOS) with standard deviation (± SD) and mean costs (± SD).  The mean LOS was 7.3 (± 0.5) days.  The mean cost per FN episode was €8,915 (± 718).  The major cost driver was hospital bed-stay (mean cost of €6,851 (± 549)).  Other cost drivers included antibacterial treatment at €760 (± 156), laboratory investigations at €538 (± 47) and the requirement for blood bank products at €525 (± 189).  CONCLUSIONS: To our knowledge, this is the first investigation of the cost of chemotherapy induced FN within the context of the Irish Healthcare setting.  Our results will be used in cost-effectiveness analyses of novel chemotherapeutic agents and interventions which prevent or treat FN.