Five million Americans suffer from heart failure (HF). Despite innovative new pharmacologic and device therapies, the 5-year mortality rate for patients remains near 50%. Conservatively, 300,000 patients with HF also have severe functional mitral regurgitation. Over the past decade, the surgical approach to these patients has become more aggressive because the extent of the problem has become widely recognized, and surgeon familiarity with annuloplasty techniques has increased. Although clinical experience and enthusiasm have resulted in an expansion of literature, the role that mitral valve repair surgery plays in the treatment of HF is not fully established. In this article, we review the existing data on the efficacy of mitral valve surgery in HF patients. Specifically, we will review the available data regarding the effect of mitral valve surgery on longevity, ventricular remodeling, and symptoms. No randomized prospective data are available, but careful analysis of existing retrospective studies allows important conclusions to be made.