Radon, a source of natural background radiation, has been a subject of extensive studies as a major causative agent of lung cancer at the domestic and international levels. This study investigated and compared domestic and international methods of radon measurement. In the United States, radon is measured through primary and secondary testing, and a similar method is used in Canada. In the United Kingdom, only long-term radon measurements are taken with seasonal adjustments. In the Republic of Korea, both long-term and short-term measurements are taken with only primary testing. Through this study, standards for domestic radon measurement methods and improvement plans could be suggested.