We assessed by flow cytometry minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) given standard-dose (SDAC) and high-dose ARA-C (HDAC) regimens. Of 163 patients enrolled, 130 (median age, 45 years; range, 18-59 years) qualified for analysis, all achieving complete remission after treatment with SDAC (n 5 78) or HDAC (n 5 52) plus etoposide and daunorubicin. Consolidation consisted of intermediate-dose ARA-C and daunorubicin. MRD negativity was significantly more frequent in the SDAC vs. HDAC arm after both induction (37% vs. 15%, P 5 0.007) and consolidation (44% vs. 18%, P 5 0.002).Respective median residual leukemic cell counts with SDAC and HDAC use were 1.5 3 10 23 and 4 3 10 23 (P 5 0.033) after induction and 5.7 3 10 24 and 2.9 3 10 23 (P 5 0.008) after consolidation. Based on ARA-C schedule and post-consolidation MRD status, the four patient groups (SDAC-MRD 2 , HDAC-MRD 2 , SDAC-MRD 1 , and HDAC-MRD 1 ) displayed 5-year overall survival rates of 60%, 33%, 24%, and 42% (P 5 0.007), respectively, with 24%, 35%, 74%, and 48% (P < 0.0001) respective cumulative incidence of relapse estimates. MRD may serve as a biomarker for optimal biologic dosing of ARA-C, and SDAC regimen appears to yield more frequent MRD negativity.