We investigated the effects of home-based daily exercise on joint mobility, functional capacity, pain, and depression in patients with ankylosing spondylitis (AS). The patients were randomly assigned to a wait-list control group or to an exercise-therapy group. The exercise-therapy group performed a 20-min exercise program once per day for 8 consecutive weeks. After 8 weeks, compared with the control group, the exercise group showed improvements in joint mobility (cervical flexion, extension, shoulder flexion, abduction, hip abduction, and knee flexion), finger-floor distance, and functional capacity. Pain and depression scores were significantly lower after the exercise program in the exercise group than in the control group. These findings indicate that exercise therapy increases joint mobility and functional capacity, and decreases pain and depression in patients with AS. Home-based exercise, which is easily accessible to patients, might be an effective intervention for AS.