This dissertation is a comparative study of Martin Heidegger's meditative thinking and Theravada Buddhist mindfulness. The main objective of this research establishes an elemental framework to understand the psychological and discerning aspects of both meditative thinking and Buddhist mindfulness for the purpose of showing differences, similarities, and ultimately harmonization. Because Buddhist mindfulness, which is essential in all schools of Buddhism, and Heidegger's meditative thinking, which was emphasized in the later writings, suggest a way towards intentional awareness and thinking Being, respectively, this dissertation is an inquiry into adequate parallels between them. Concurrent objectives are: (1) to understand mindfulness and meditative thinking from their historical roots and contemporary interpretations, (2) to show their psychological and discerning aspects, and (3) build bridges between these two diverse concepts and their respective traditions for a contribution to the realm of philosophical psychology. In addition to the basic comparative methodology, an integral strategy will be employed to complement the basic comparative perspective. This perspective will emphasize integration and potentiality rather than differentiation and dissonance. The dissertation concludes with a summary of the findings and suggestions towards a psychology of meditative thinking.