Currently, 17% of individuals over age 50, and 6% of individuals over age 65, have tried mind-body therapies (Wolsko et al., 2004); 16.5% of yoga practitioners are age 54 or older (Saper et al., 2004). National survey data indicates a large portion of mind-body therapy users implement these practices for the management of disorders, which are either psychological or psychosomatic. Among yoga practitioners, 63.7% reported implementing yoga techniques for wellness and preventative benefits, and 47.9% reported implementing yoga techniques for the management of specific health conditions. Because increasing numbers of older adults are engaged in yoga, it is important to understand how yoga impacts this population. Older adults (N = 98; Mean age = 77.04, SD = 7.28) were randomly assigned to 3 groups: Chair Yoga, Chair Exercise, and no-treatment control group. Classes were held for 45-minute weekly sessions, over six weeks, and daily home practice was supported. All participants were assessed pre-intervention, post-intervention, and at one-month follow-up for anger, anxiety, depression, well-being, general self-efficacy, and self-efficacy for daily living. Time by group interactions were significant for all trait variables. Yoga participants improved more than both exercise and control participants, in anger (ES = 1.01, 0.12, and 0.11 respectively, from pretest to posttest; and 0.89, -0.01, and 0.17 from pretest to follow-up), anxiety (ES = 0.58, 0.31, 0.18, and 0.89, 0.28, 0.27), depression (ES = 0.53, 0.07, 0.05, and 0.54, 0.01, 0.04), well-being (ES = 0.49, 0.36, 0.01, and 0.53, 0.28, -0.08), general self-efficacy (ES = 0.98, 0.35, -0.12, and 0.73, 0.43, -0.12), and self-efficacy for daily living (ES = 0.87, 0.35, 0.07, and 0.51, 0.24, 0.09). Changes in self-control were associated with changes in general self-efficacy and trait anxiety. Self-control is proposed as a mechanism underlying the impact of yoga on psychological health.