Background Elderly patients are under-represented in most surgical series of mitral valve surgery. The impact of preoperative heart failure (HF) on the outcomes of this subset has not been extensively studied. Methods and results The study included 45,082 Medicare beneficiaries who underwent primary isolated mitral valve repair (MVP) (n = 16,850) or replacement (MVR) (n = 28,232) from 2000 to 2009. Medicare claims from the year before and the year of the index hospitalization were reviewed for documentation of HF to examine the operative mortality and long-term survival of patients with and without preoperative HF. Preoperative HF was present in 52.5% and 64.8% of patients who underwent repair and replacement, respectively. Duration of HF greater than 3 months was present in a significant proportion of patients (18.2% for MVP and 22.7% for MVR). Adjusted operative mortality was higher for patients with preoperative HF (MVP odds ratio [OR], 1.46; 95% confidence interval [CI], 1.21-1.78; MVR OR, 1.36; 95% CI, 1.23-1.51). Patients without preoperative HF had better long-term survival (MVP hazard ratio [HR], 2.23 [95% CI, 2.09-2.36]; MVR HR, 1.80 [95% CI, 1.73-1.86]). After adjustment, a preoperative HF diagnosis was still associated with 52% and 36% increased risk of death over the 10-year follow-up period for patients who underwent MVP and MVR, respectively. Preoperative HF duration greater than 3 months conferred an excess 28% higher risk of death on long-term follow-up compared with patients with HF less than 3 months. Conclusions Preoperative HF is present in a large number of elderly patients undergoing primary isolated mitral valve surgery and adversely affects their short-term and long-term survival, irrespective of procedure type (repair or replacement). The study supports the early identification of elderly patients with mitral valve disease and referral to surgery before the onset of HF.