A 61-year-old man with hypertrophic obstructive cardiomyopathy was treated twice with percutaneous transluminal septal myocardial ablation (PTSMA). The first procedure improved the left ventricular outflow tract pressure gradient (LVOTG) from 148 to 48 mmHg and the New York Heart Association (NYHA) class from III to II in a week. However, the LVOTG increased to 197 mmHg and the NYHA class worsened to III within 3 months. In spite of medical treatment with beta-blocker, syncope attack occurred suddenly. Repeated PTSMA was performed. Just after the second procedure, the LVOTG did not decrease. However, the LVOTG decreased to 81 mmHg and the NYHA class improved to II with 3 months. The different response of pressure gradient in the acute and chronic phase with repeated PTSMA was interesting.