Being attentive to and aware of one's experiences in the present moment with qualities of acceptance and openness reflects the state of mindfulness. Positive associations exist between state mindfulness and state autonomous motivation for everyday activities. Though this suggests that state mindfulness links with adaptive motivational experiences, no suitable measure of state mindfulness exists that would facilitate the examination of these relationships in a physical activity context. Thus, we revised the State Mindfulness Scale (Tanay & Bernstein, 2013) and provided score validity evidence for the measure in a physical activity context. A bi-factor model reflecting mindfulness of the mind and body as specific factors and a general mindfulness factor was supported. Validity evidence, such as positive relationships with intrinsic motivation, and a negative relationship with body surveillance support score use. The revised scale can facilitate investigations of the role of mindfulness in physical activity settings.