There is substantial evidence for a significant genetic component to the risk of alcoholism. In searching for genes that contribute to this risk, several approaches may be utilized in order to identify the genetic loci underlying alcoholism susceptibility. Several candidate genes have been evaluated for their role in alcoholism; however, with the exception of the enzymes of alcohol metabolism, results from these studies have been inconsistent. Recently, two large studies have employed a genome screen methodology to identify novel genes contributing to the risk of alcoholism. As an alternative strategy, researchers have utilized mouse and rat models to identify quantitative trait loci influencing alcohol preference. Through the development of congenic lines and transgenic and knock-out animals, candidate genes can be identified and evaluated for their role in alcohol preference.