6089 Background: Febrile neutropenia (FN), a dose-limiting event for many myelosuppressive chemotherapy (CT) regimens, often causes subsequent CT dose delays (DD) and reductions (DR), lengthens hospital stay and increases monitoring, diagnostic and treatment costs. No studies are known to date on economic costs of FN in common clinical practice in Spain. Methods: This is a multicentre, retrospective, observational chart review of adult patients with breast cancer, lung cancer or non-Hodgkin’s lymphoma (NHL) who suffered from at least one FN episode related to cytotoxic CT from 16 Spanish hospitals. Resource use and subsequent costs including days of hospitalization, number of RBC transfusions, number and type of complementary tests, use of colony-stimulating factors (CSF), antibiotics and other drugs to manage FN were assessed. Potential impact of FN on planned CT dose and/or schedule was also analysed. P-value was obtained by one-way ANOVA using the Bonferroni correction. Results: A total of 194 medical charts including 238 documented FN episodes were reviewed. Women, 59.8%; age > 60 yrs, 49.5%; breast cancer, 43% (83% treated with taxane or anthracycline-based CT); lung cancer, 22% (95.5% treated with platinum-based CT); NHL, 35% (58.2% treated with CHOP-like CT). Hospitalization due to FN lasted a median of 7 days. During the episode, 32.3% of pts needed 1 or more RBC transfusions, 97.9% required a blood test and 87% a blood culture. CSFs were used in 67.6% of pts. All pts were treated with antibiotics and 78.2% with other drugs. 58.4% of FN episodes had an impact on planned CT dose and/or schedule: DR was observed in 34.9% of cases, DD in 28% and CT withdrawal in 14.7%. Conclusions: Main drivers of cost of FN are hospitalization and antibiotic treatment. FN is more costly in NHL pts than breast or lung pts (statistically significant in lung pts). FN episodes have a relevant impact on planned CT dose and/or schedule. In each row statistically significant differences ( p<0.05) were obtained between values with the same letter. [Table: see text] [Table: see text]