Although chronic lymphocytic leukemia (CLL) is a disease of elderly patients, subjects older than 65 years are heavily underrepresented in clinical trials. The German CLL study group (GCLLSG) initiated a multicenter phase III trial for CLL patients older than 65 years comparing first-line therapy with fludarabine with chlorambucil. A total of 193 patients with a median age of 70 years were randomized to receive fludarabine (25 mg/m(2) for 5 days intravenously, every 28 days, for 6 courses) or chlorambucil (0.4 mg/kg body weight [BW] with an increase to 0.8 mg/kg, every 15 days, for 12 months). Fludarabine resulted in a significantly higher overall and complete remission rate (72% vs 51%, P = .003; 7% vs 0%, P = .011). Time to treatment failure was significantly shorter in the chlorambucil arm (11 vs 18 months; P = .004), but no difference in progression-free survival time was observed (19 months with fludarabine, 18 months with chlorambucil; P = .7). Moreover, fludarabine did not increase the overall survival time (46 months in the fludarabine vs 64 months in the chlorambucil arm; P = .15). Taken together, the results suggest that in elderly CLL patients the first-line therapy with fludarabine alone does not result in a major clinical benefit compared with chlorambucil. This trial is registered with www.isrctn.org under identifier ISRCTN 36294212.