Since the American Revolution, citizen soldiers have raised their right hands and taken the oath of allegiance to “support and defend the Constitution of the United States” (Center of Military History, 2004). Because of this long tradition and pride, the U.S. military takes a hard line when it comes to the use and abuse of chemicals among its members. is chapter provides a brief historical view of substance use disorders in the military, as well as a discussion about the appropriate assessment, discipline, and treatment. e clinician will nd information geared toward developing a better understanding of these disorders and preparing appropriate treatment plans for service members. Several aspects of therapy are discussed, as are various issues that may arise when working with these patients.