The International Commission on Radiological Protection (ICRP) states that particular attention should be paid to radiation effects on the cardiovascular system because of recent published observations of their effects occurring at lower doses than previously reported (ICRP, 2007 and2012). The review was based on scientific articles available in open literature and major reviews by organizations, in particular ICRP118. In this review, we describe the low-dose ionizing radiation effects, the causes of cardiovascular diseases (CVDs), the relationship between low-dose ionizing radiation and CVDs, and the importance of elucidating the relationship between low-dose ionizing radiation and CVD.