The purpose of this study was to examine the feasibility of a self-efficacy based intervention using Wii exergames in assisted living residents. The study was a single-group pre- and post-test design. Seven older adults (aged 80–94 years) were instructed to engage in exergames twice a week for 8 weeks. Physical function (balance, mobility, and walking distance), fear of falling, self-efficacy for exercise, and outcome expectations for exercise were evaluated. All participants had enjoyable experiences and no serious adverse events were reported. Participants had significant improvement on balance. Although not significant, there were trends indicating that participants improved mobility, walking endurance, and decreased fear of falling. The use of Wii exergames was an acceptable, safe, and potentially effective approach to promote physical activity in older adults. Findings provide support for the applications of integrating self-efficacy theory into exergames as a mechanism to encourage older adults to engage in exercise.