For degenerative mitral disease, repair is superior to replacement; however, the best operative strategy for rheumatic mitral disease remains unclear. We evaluated the association between decision-making in choosing repair versus replacement and outcomes across 2 decades of rheumatic mitral surgery. Patients undergoing isolated, first-time rheumatic mitral surgery were identified. Era 1 (1997-2008) and Era 2 (2009-2018) were distinguished by intraoperative assessment of anterior leaflet mobility/calcification (Era 2) in deciding between mitral repair versus replacement. Primary outcome was a composite of death, reoperation, and severe valve dysfunction. Among 180 patients, age was 59 ± 14 years, and ejection fraction was 58% ± 10%. A higher proportion in Era 1 (n = 56) compared with Era 2 (n = 124) had preoperative atrial fibrillation (68% vs 46%; P = .006); the groups were otherwise similar. Primary indication was mitral stenosis in 69% (124 out of 180; pure = 35, mixed = 89) and did not differ by era (P = .67). During Era 1, 70% (39 out of 56) underwent repair, compared with 33% (41 out of 124) during Era 2 (P < .001). Freedom from death, reoperation, or severe valve dysfunction at 5 years was higher in Era 2 (72% ± 9%) than Era 1 (54% ± 13%; P = .04). Five-year survival was higher in Era 2 than Era 1, but did not differ between repair versus replacement. Five-year cumulative incidence of reoperation with death as a competing risk did not differ by era, but was higher after repair than replacement. Careful assessment of anterior leaflet mobility/calcification to determine mitral repair or replacement was associated with improved outcomes. This decision-making strategy may alter the threshold for rheumatic mitral replacement in the current valve-in-valve era. Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.