Chronic lymphocytic leukemia of the B-cell type (B-CLL) is the most frequently occurring leukemia in the Western hemisphere. Until 10 years ago, the basic medical approach to this disease was expectative and palliative. Chemotherapy with alkylating agents such as chlorambucil used to be the main therapeutic option, and only patients at advanced stages of B-CLL were treated. With the advent of new treatments such as purine analogs, high-dose therapy followed by hematopoietic progenitor support, monoclonal antibodies, and further immunotherapies, this paradigm is about to change. By using these combinations, younger patients with active disease are now treated with the goal of a long-lasting remission. More sophisticated techniques allow characterization of some of the underlying molecular genetic aberrations and (together with new serum parameters) more accurate prediction of individual prognoses than with the clinical staging systems. With the help of these developments, patients with B-CLL will be managed according to their individual risk with a watch-and-wait strategy in patients with the most indolent form of the disease, conventional chemotherapy with alkylating agents and/or purine analogs in patients at intermediate risk, and aggressive high-dose chemotherapy (followed by immunotherapy) in patients with the most aggressive form of the disease.