BACKGROUND:This study investigated whether mindfulness training increases athletes' mindfulness and flow experience and decreases sport-specific anxiety and sport-specific pessimism. METHODS: Cyclists were assigned to an eight-week mindfulness intervention, which incorporated a mindful spin-bike training component, or a wait-list control condition. Participants completed baseline and post-test measures of mindfulness, flow, sport-anxiety, and sport-related pessimistic attributions. RESULTS: Analyses of covariance showed significant positive effects on mindfulness, flow, and pessimism for the 27 cyclists in the mindfulness intervention condition compared with the 20 cyclists in the control condition. Changes in mindfulness experienced by the intervention participants were positively associated with changes in flow. CONCLUSIONS: Results suggest that mindfulness-based interventions tailored to specific athletic pursuits can be effective in facilitating flow experiences.