Background. Chemotherapy for the treatment of early-stage breast cancer (ESBC) patients improves survival outcomes. However, its most common acute toxicity is myelosuppression, which can reduce the delivered dose and compromise the survival benefit. Because FEC100-docetaxel (FEC100-D) is a common protocol for ESBC, we evaluated its febrile neutropenia (FN) incidence and the role of its hematological toxicity on the individual relative dose-intensity (RDI). Patients and methods. It is a French single-center, observational, retrospective study. Patients received adjuvant/neoadjuvant FEC100-D treatment, without primary prophylaxis by granulocyte colony-stimulating factors (G-CSF). The neutrophil count the day before the planned chemotherapy cycle had to be over 1,500.mm^-3 for the treatment to be administered. Data collected included: date and dose of chemotherapy cycles, FN and high grade of hematological toxicity occurrence for each course, G-CSF prescription. Results. One thousand, seven hundred and fifty-seven cycles in 284 patients were delivered. FN was observed in 4.9% (n=14) of the patients, without hospitalizations or deaths after. Grade 3-4 neutropenia occurred in 5.8% of the cycles, during the first cycle in 40% of cases. Seventeen percent of our patients received less than 85% of RDI. Conclusion. The hematotoxicity of this treatment is acceptable. The risk of FN is low. No G-CSF primary prophylaxis is needed without additional risk factor.