Addiction researchers have unique ethical and legal considerations in designing studies that protect participants who use substances. Ethical principles (including autonomy, nonmaleficence, beneficence, veracity, fidelity, and justice) along with federal and state regulations provide guidance to researchers conducting addictions outcome research. When designing substance use research, particular attention needs to be given to informed consent, compensation, confidentiality, and collection and protection of data. Furthermore, researchers must avoid coercion, provide alternative treatment options, protect vulnerable clients, and select representative participants for addictions research. The ultimate goal of addictions outcome research is to benefit the research participants and society as a whole.