The hypomethylating agents, decitabine (DEC) and azacitidine (AZA), allowed more elderly acute myeloid leukemia (AML) patients to be treated. However, there are little direct comparative data on AZA and DEC. This multicenter retrospective study compared the outcomes of AZA and DEC in terms of response and overall survival (OS). Potential predictors associated with response and OS were also evaluated. A total of 626 AML patients were included (487 treated with AZA and 139 with DEC). Response rates were similar in both groups: CR was 18% with AZA vs. 23% with DEC (p = 0.20), CR/CRi was 20.5% vs. 25% (p = 0.27) and ORR was 32% vs. 39.5% (p = 0.12), respectively. Patients with leukocytes < 10 × 109/L, bone marrow blasts < 50% and ECOG ≥ 2 had higher ORR with DEC than with AZA. OS was similar in both groups: 10.4 months (95% CI: 9.2−11.7) vs. 8.8 months (95% CI: 6.7−11.0, p = 0.455), for AZA and DEC, respectively. Age (≥80 years), leukocytes (≥ 10 × 109/L), platelet count (<20 × 109/L) and eGFR (≥45 mL/min/1.73 m2) were associated with higher OS with AZA compared to DEC. In conclusion, we found no differences in response and OS rates in AML patients treated with AZA or DEC.