Given the prevalence of regular marijuana use among adolescents and associated risks for adverse consequences to functioning, effective interventions are needed that are tailored for this population. To date, most such counseling approaches have relied on non-voluntary participation by adolescent marijuana smokers and the outcomes have been only modestly successful. The Teen Marijuana Check-Up is a brief motivational enhancement intervention publicized as a non-pressured and confidential opportunity for the teen marijuana smoker to "take stock" of his/her use. The intervention is designed for in-school implementation and intended to elicit the teen's voluntary participation. This paper highlights the manner in which adolescents are recruited, key intervention elements, the nature of the counseling style utilized, and clinical challenges. The outcomes of two trials with this intervention are briefly discussed.