Background.Although the life expectancy of patients with FL has recently increased, notably since the introduction of rituximab in combination with chemotherapy, little is known regarding the precise causes of patients death. Patients and methods'. This study describes the different causes of death in FL patients among followed since 2000 at Lyon University Hospital, centre Léon Bérard and Mayo Clinic. The causes of death will be classified as related to lymphoma progression, treatment-related toxicity (including TRM and secondary myelodysplastic syndrome/acute myeloid leukemia), secondary neoplasias, or other.