Methamphetamine use and its social and health consequences pose a serious public health challenge in the United States and beyond. The focus of this article is on functional methamphetamine use from the insider's perspective. In-depth interviews were conducted in Atlanta, Georgia with 40 heavy methamphetamine users. Heavy use was defined as having used methamphetamine at least 10 times during the 30 days prior to the interview. For these respondents, functional use comprised using methamphetamine to improve an action or skill. Further exploration resulted in three recurrent categories of functional use. These include enhanced functioning, increased productivity, and the ability to function normally while using methamphetamine. It is argued that functional drug use may not be unique to methamphetamine. In addition, the findings show the importance of incorporating the complexities of functional use in future studies as well as risk reduction and treatment services targeting drug users.