Copy number variations (CNVs) that are frequent in genome influence on susceptibility of various diseases including cancers. The present mini-review focuses on CNVs associated with susceptibility to the cancers. Since CNVs are different between cancer types, the analysis of the specific CNV makes it possible to estimate the susceptibility to the cancers of interest in individuals. Although it is true that available data on CNVs associated with cancer susceptibility are limited at present, accumulation of the data is accelerated with the research progression of CNVs in near future. Information on CNVs associated with cancer susceptibility is useful for not only cancer research but also personalized healthcare including cancer prevention.