Alcoholism has a significant genetic basis, and identifying genes that confer a susceptibility to alcoholism will aid clinicians in preventing and effectively treating the disease. One commonly used technique to identify genetic risk factors for complex disorders such as alcoholism is the candidate gene approach, which directly tests the effects of genetic variants of a potentially contributing gene in an association study. These studies, which may include members of an affected family or unrelated cases and controls, can be performed relatively quickly and inexpensively and may allow identification of genes with small effects. However, the candidate gene approach is limited by how much is known of the biology of the disease being investigated. As researchers identify potential candidate genes using animal studies or linking them to DNA regions implicated through other analyses, the candidate gene approach will continue to be commonly used.