ABSTRACT This prospective study has estimated outcomes in 509 elderly AML patients with different treatment approaches depending on ECOG performance status and the Charlson Comorbidity Index (CCI). Patients were stratified into fit (ECOG 0-2 and CCI 0-2) or frail (ECOG >2 and/or CCI >2) groups. The fit patients with CCI 0 received intensive chemotherapy whilst reduced-intensive chemotherapy (R-IC) was given to those with CCI 1-2. The frail patients received the best supportive therapy. The fit patients presented a longer overall survival (OS) than frail subjects but 8-week mortality rates were similar. The CR ratio between fit CCI 0 and CCI 1-2 subgroups was significantly different. Both of the fit subgroups showed similar 8-week mortality rates and OS probabilities. Allocating the fit patients with CCI 1-2 to R-IC enabled to increase the group of elderly patientswho could be treated with the intention of inducing remission.