ECG is included in certain medical examinations of insurance application, ECG has low specificity and sensitivity. So ECG is not usually used to diagnose specific diseases. But, ECG is not invasive and costs low. So ECG is usually used in underwriting. Actually in underwriting we meet various ECG patterns and diagnosises. Understanding of various ECG patterns is different between insurance medicine and clinical medicine. So We have to learn various ECG patterns and effects on mortality and morbidity. First considerations of ECG readings are age, sex, blood pressure, family history, smoking historyalcohol history and hyperlipidemia. These are predictors for possibility of disease. Also it is important to review recording ECG with proper skill. In this review I consider several ECG diagnosises that we meet frequently, which is, LVH, RVH, ST abnormalities, LBBS, RBBB, A-B blocks, several kinds of arrhythmia. We have to consider long term mortalities and morbidities of specific ECG patterns although applicants have no symptom and sign. And then we have to make underwriting manual according to specific ECG diagnosises and patterns and underwrite precisely ECG patterns according to insurance products. Nowadays coronary heart disease and other heart diseases are increasing in Korea. So we have to learn various ECG patterns and research mortalities and morbidities of abnormal ECG patterns. Also we have to apply to more broad, precise underwriting skills about ECG patterns and diagnosises.