This study was designed to investigate the effects of exercise therapy on joint mobility, daily activity. pain and depression of patients with ankylosing spondylitis. 25 persons with the experimental group and 25 persons with the control group were conveniently sampled among out-patients diagnosed with ankylosing spondylitis at the rheumatism center of H University Medical Center. The control patients were matched to the experimental group and they were selected considering sex and age. The exercise therapy was developed by the author with the assistance of exercise specialists. The program includes muscle relaxation, flexibility, muscle strengths, breathing strengths and straight posture exercises. The 20-minute exercise therapy was carried out to the experimental group once a day for eight weeks from October. 1997 to February, 1998. Before and after the experiments, joint mobility, daily activity, pain and depression were measured respectively. Data were analyzed by $chi$$^2$-test. t-test, paired t-test and unpaired t-test. The results were as follows : Joint mobility(cervical flexion, extension, shoulder flexion, abduction, hip abduction, knee flexion and fingertip to floor distance) and daily activity in the experimental group after the exercise were significantly increased than that in the control group. The pain and depression score in the experimental group after the exercise were significantly decreased than that in the control group. These findings may indicate that the exercise therapy is effective in increasing the joint mobility and daily activity, and also effective in decreasing pain and depression in patients with ankylosing spondylitis, Accordingly, the exercise therapy can be adopted as an effective nursing intervention for ankylosing spondylitis.