Mindfulness, the core teaching of the Buddhist tradition, has been receiving serious attention from the West in recent decades as evidence of the efficacy of mindfulness-based interventions for emotional distress have become available. Although traditional Buddhist texts have described the mechanisms of mindfulness and the way to cultivate it in great detail, much is still not known from the perspective of Western science. In particular, there is no general agreement on the conceptualization and operationalization of mindfulness. Several conceptual models of mindfulness (referred to as "state" or "trait") have been put forward to elucidate different aspects of this phenomenon, but none has gained sufficient empirical validation. This article proposes a new cognitive model of mindfulness. It has been our goal to describe and interrelate a relatively comprehensive group of determinants of a state of mindfulness, the consequences of its regular practicing, the mechanisms responsible for its beneficial effects, and the feedback mechanisms operating between the various constituents of the model. Within this model, the primary emphasis has been placed on understanding the cognitive processes shaping a state of mindfulness (i.e., the links between consciousness, meta-awareness and the unconscious), and on their determinants (i.e., the executive functions of attention and the components of working memory). A metacognitive system promoting mindfulness, as well as the general capability of the central executive system, is suggested as a factor explaining individual differences in mindfulness, whereas decentering, self-compassion, and reduction of self-focused attention are proposed as mechanisms mediating beneficial changes. We hope that the model presented will encourage further discussion and orient future studies in the area of mindfulness.