This thesis attempts to bring the practice and psychological orientation of mindfulness(sati) in the Buddhist tradition more into focus. The popularized rhetoric and growing catalog o fmindfulness practices today require that the grounding of Buddhist mindfulness be exposed.Therefore, by showing some of this grounding I begin to reveal and clarify ambiguities that lie at the heart of this Buddhist practice. After giving a basic outline of the Buddhist worldview, I display some of the origins and early meanings of the Sanskrit word smirti, from which the Paliword sati is derived. Sati is then examined alone and in conjunction with the meditative practicewith which it is associated, the satipatthana (foundation of mindfulness). By tracing sati througha set of lists collectively known as the Bodhi-pakkhiya-dhamma, I show some of the interconnected roles mindfulness plays in the tradition. Finally, I briefly display claims made by contemporary practitioners and therapeutic practices for possible comparison. In conclusion, the multitude of historical, praxis-oriented, and psychological factors that constitute and support Buddhist mindfulness make it difficult to isolate a single definition of this central Buddhist concern.