Mindfulness has been found to be beneficial to psychological health. Furthermore, research suggests that mindfulness is associated with better attention control and fewer difficulties in emotion regulation. The purpose of the current study was twofold. First I investigated whether attention control and emotion regulation are mechanisms of mindfulness that aid performance on two cognitive tasks. Second, I investigated whether mindfulness moderates the relationship between rumination, a risk factor for mental health, and cognitive interference. In this study, participants completed two cognitive tasks that measure interference from emotional stimuli. They also completed self-report questionnaires that measure levels of mindfulness, attention control, difficulties in emotion regulation, and rumination. The results indicated that mindfulness was related to attention control, difficulties in emotion regulation and rumination. However, mindfulness did not predict attentional performance as measured by cognitive interference. It was also found that mindfulness did not moderate the impact of rumination on cognitive performance.