Mitral regurgitation is a valvular heart lesion that is difficult to diagnose accurately; thus, it is difficult to determine the appropriate timing for surgical correction. With increasing use of reparative techniques, including local resection of valve pathology and placement of an annuloplasty ring, and the realization that chronic atrial fibrillation leads to decreased long-term survival, the timing of surgery has changed. In addition, serial noninvasive studies have indicated that despite the absence of symptoms, patients may progress to a myopathic condition if the regurgitation progresses over a long period and surgery is not performed when signs of left ventricular dysfunction are evident. Preservation of the papillary muscle is also extremely important for late postoperative function in patients with mitral regurgitation, and reparative surgery that preserves both anterior and posterior papillary muscle complexes and continuity with the anulus appears to satisfy this assumption. Worldwide experience is reviewed and I present conclusions related to the appropriate indications for mitral valve repair or replacement in patients with mitral regurgitation.