First sessions of psychotherapy present a rare and potent opportunity for therapists and clients alike. Motivational interviewing is established as a stand-alone method for promoting behavior change as well as a useful prelude to other therapies. This article provides a rationale and empirical support for the use of motivational interviewing in first psychotherapy sessions. A case illustration and practical guidelines for therapists are included. (PsycINFO Database Record (c) 2019 APA, all rights reserved)