Chronic lymphocytic leukemia (CLL) is the most frequent form of leukemia in the Western World. The disease is characterized by the accumulation and proliferation of mature, monoclonal, CD5+ B-cells with specific immunophenotype in the peripheral blood (above 5x109/L), bone marrow and secondary lymphoid organs. Small lymphocytic leukemia (SLL) is characterized by similar tumor cells but without increased lymphocyte count. The management of these patients have considerably changed over the last decade. Indeed, beyond chemo-immunotherapy, multiple targeted therapies have been approved on the basis of phase 2 and randomized phase 3 clinical trials and have subsequently been used in daily practice. The management of patients with SLL is similar to that of those with CLL. In addition to therapeutic advances, the advent of new sequencing technologies has also identified CLL genetic features that are now being incorporated in patient routine evaluation. We here propose to set a large-scale prospective and non-interventional study including patients with symptomatic CLL/SLL with the aim to evaluate the real-world clinical management of these patients and to identify the impact of treatments and therapeutic trajectories on long-term outcome.