Genetic research on addiction liability and pharmacogenetic research on treatments for addiction have identified some genetic variants associated with disease risk and treatment. Genetic testing for addiction liability and treatment response has not been used widely in clinical practice because most of the genes identified only modestly predict addiction risk or treatment response. However, many of these genetic tests have been commercialized prematurely and are available direct to the consumer (DTC). The easy availability of DTC tests for addiction liability and lack of regulation over their use raises a number of ethical concerns. Of paramount concern is the limited predictive power and clinical utility of these tests. Many DTC testing companies do not provide the consumer with the necessary genetic counselling to assist them in interpreting and acting on their test results. They may also engage in misleading marketing to entice consumers to purchase their products. Consumers' genetic information may be vulnerable to misuse by third parties, as there are limited standards to protect the privacy of the genetic information. Non-consensual testing and inappropriate testing of minors may also occur. The United States Food and Drug Administration plans to regulate DTC genetic tests. Based on the ethical concerns we discuss below, we believe there is a strong case for regulation of DTC genetic tests for addiction liability and treatment response. We argue that until this occurs, these tests have more potential to cause harm than to contribute to improved prevention and treatment of addiction.