Previous studies have reported satisfactory long-term results of mitral valve (MV) repair for rheumatic mitral disease. However, the effects of this procedure in isolated rheumatic mitral stenosis remain unclear. In addition, protective effects of MV repair on cardiac function have not been verified in rheumatic MV disease. This study retrospectively evaluated early mortality and mid-term results of MV repair for isolated rheumatic mitral stenosis in a mid-volume cardiac centre, and explored the effects of this procedure on cardiac function. Between January 2015 and May 2021, 360 patients with isolated rheumatic mitral stenosis and combined (concomitant) atrial fibrillation (AF) underwent MV repair (100 patients) or MV replacement (260 patients). Perioperative characteristics were compared between the two groups and a regression analysis for early mortality and mid-term left ventricular ejection fraction was conducted. In addition, mid-term survival was compared between the two groups. Baseline characteristics of the two groups were balanced after matching. Compared with patients in the replacement group, patients with MV repair had a lower occurrence of postoperative hypotension and AF. There was no difference in early mortality or mid-term survival between the two groups. However, MV repair was associated with a higher mid-term left ventricular ejection fraction. During follow-up, four thromboembolic events and four haemorrhagic events occurred in the replacement group. No blood coagulation-related complications occurred in the repair group. Mitral valve repair for isolated rheumatic mitral stenosis and concomitant AF was feasible in a mid-volume cardiac centre, with satisfactory perioperative results and mid-term outcomes. Furthermore, this procedure preserved mid-term left ventricular systolic function.