Background: Although it has been realized that restrictive mitral valve annuloplasty (MVA) may result in clinically significant functional mitral stenosis (MS), it still cannot be predicted. The purpose of this study was to identify risk factors for clinically significant functional MS following restrictive MVA surgery for chronic ischemic mitral regurgitation (CIMR). Methods: One hundred and fourteen patients who underwent restrictive MVA with coronary artery bypass grafting (CABG) for treatment of CIMR were retrospectively reviewed. Clinically significant functional MS was defined as resting transmitral peak pressure gradient (PPG) >= 13 mmHg. Results: During the follow-up period (range 6-12 months), 28 (24.56%) patients developed clinically significant functional MS. The PPG at follow-up was significantly higher than that measured in the early postoperative stage (3-5 days after surgery). Moreover, there was a linear correlation between the two measurements (r = 0.398, p < 0.001). Annuloplasty size <= 27 mm and early postoperative PPG >= 7.4 mmHg could predict clinically significant functional MS at 6-12 months postoperatively. Conclusions: Chronic ischemic mitral regurgitation patients treated with restrictive MVA and CABG have significant increases in PPG postoperatively. Annuloplasty size <= 27 mm and early postoperative PPG >= 7.4 mmHg can predict clinically significant functional MS at 6-12 months after surgery.