We report an 84-year-old woman who presented with right ventricular perforation 4 days after pacemaker implantation for syncope due to sick sinus syndrome. Median sternotomy revealed no pericardial effusion, but the pacing lead had penetrated the right ventricle and pericardium. When the pleura was opened, the tip of the lead was seen in the visceral pleura. The lead was cut in the pericardial cavity and extracted from the left subclavian wound together with the generator. The right ventricular perforation was sutured and a temporary pacing lead was placed on the right ventricular wall intraoperatively. Ten days after the surgery, a new pacemaker lead was placed in the ventricular septum via the right axillary vein. Right ventricular perforation is a rare complication after pacemaker implantation. Typically, it occurs at the time of implantation or within 24 hours after implantation. In the present case, the perforation of the right ventricle which needed urgent surgery occurred 4 days after implanting the pacing lead at the right ventricular apex. Great care should have been taken not to overlook this life-threatening complication even more than 24 hours after pacemaker implantation.