A 70-year-old man complaining of exertional dyspnea was referred to our hospital for recurrence of mitral regurgitation (MR) after mitral valve repair. Echocardiography revealed the presence of a bulging subaortic septum with flow acceleration in the left ventricular outflow tract (LVOT) and systolic anterior motion of the mitral valve with moderate MR, consistent with LVOT obstruction. Since medical therapy was not sufficiently effective, we performed percutaneous transluminal septal myocardial ablation (PTSMA). After the procedure, the MR resolved, with a reduced LVOT pressure gradient. The patient's symptoms improved. PTSMA was effective for the treatment of MR that emerged after mitral valve repair.