Cardiac arrhythmias and syncope are rare consequence of therapy with pegylated interferon. We report a 55-year-old Egyptian woman who developed palpitation and syncopal attacks twice within 3 months after starting therapy with pegylated interferon α2b and ribavirin for the treatment of chronic hepatitis C virus. Hepatitis C virus-RNA was undetectable after 12 week. The electrocardiogram holter revealed ventricular extra-systoles on top of sinus tachycardia. pegylated interferon α2b therapy was continued but with a reduced dose. Close follow up revealed neither palpitation nor syncope and hepatitis C virus-RNA was undetectable at 24 and 48 weeks of treatment. In conclusion, our study suggests readjustment of the dose of pegylated interferon α2b therapy to avoid these serious side effects.