This article reviews the ways in which mindfulness practices have contributed to cognitive and behavioral treatments for depression and anxiety. Research on mindfulness-based interventions (MBIs) has increased rapidly in the past decade. The most common include mindfulness-based stress reduction and mindfulness-based cognitive therapy. MBIs are effective in reducing anxiety and depression symptom severity in a range of individuals. MBIs consistently outperform non-evidence-based treatments and active control conditions, such as health education, relaxation training, and supportive psychotherapy. MBIs also perform comparably with cognitive behavior therapy (CBT). The treatment principles of MBIs for anxiety and depression are compatible with standard CBT.