We experienced two patients with serious arrhythmias associated with the administration of ledipasvir (LDV) and sofosbuvir (SOF). Neither patient took amiodarone, an agent for which concomitant use is prohibited. One patient was 82 years old and hypertensive; the other was 72 years old and had no cardiovascular risk factors such as hypertension or diabetes mellitus. The arrhythmias were both serious ventricular tachycardia (VT) that converted spontaneously to sinus rhythm, without treatment, and both patients had good outcomes. These cases suggest that LDV/SOF may be associated with an increased risk of heart-related events.