The purpose of this study was to investigate the effect of lumbar stabilization training and additional thoracic mobilization on pain, proprioception and static balance in patients with chronic low back pain. The subjects of this study were 48 chronic low back pain patients who were randomly allocated to an experimental group 1 (n1=16, lumbar stabilization and thoracic mobilization, thoracic hypomobility), experimental group 2 (n2=16, lumbar stabilization and thoracic mobilization, thoracic normal mobility), and a control group (n3=16, lumbar stabilization, thoracic hypomobility) after a thoracic mobility test. Both experimental groups underwent lumbar stabilization training and additional thoracic mobilization. The control group underwent only lumbar stabilization training. The intervention was performed 3 times per week, 30 minutes each time, for a total of 6 weeks. Thoraco-lumbar joint reposition error was measured using an electrogoniometer and static balance ability was measured using the Tetrax posture analysis system. Subjects’ pain level was measured using a 100 ㎜ visual analogue scale. Statistical analyses were performed using a one-way analysis of variance and a paired t-test. Post-hoc testing was carried out with a Bonferroni test. The pain level was significantly lower in both experimental groups compared to the control group. Both experimental groups showed significant reductions in joint reposition error angle (flexion, extension, and side bending) compared to the control group. The static balance level was significantly lower in both experimental groups than in the control group. In summary, lumbar stabilization exercises and additional thoracic mobilization significantly improved the pain level, proprioception, and static balance in patients with chronic low back pain.