ABSTRACT The AVIDA registry evaluated azacitidine usage and effectiveness in unselected MDS patients in community practice. Treating physicians made all treatment decisions. Hematologic improvement (HI) and transfusion independence (TI) assessments used IWG-2000 criteria. Enrolled were 421 MDS patients (n=228 IPSS lower-risk, n=106 higher-risk, 86 patients unclassified) from 105 U.S. sites. Median follow-up was 7.6 months (range: 0.1-27.6). HI and RBC TI rates were similar regardless of administration route or dosing schedule. Safety and tolerability were consistent with previous reports. The AVIDA registry data support azacitidine effectiveness and safety in lower- or higher-risk MDS patients treated in community practice.