['We examined the relationships between depressive symptoms, pain severity, and pain self-efficacy (PSE) in patients with chronic low back pain (CLBP). We hypothesized that change in depressive symptoms would significantly influence change in pain severity, and that PSE indirectly affects this relationship.', 'Participants were 109 CLBP patients in a 4-week multidisciplinary rehabilitation program for CLBP. They completed measures of PSE, depression, and pain severity at admission and discharge. Structural equation modeling was used to test the significant direct and indirect effects from pretreatment to posttreatment.', 'Change in depressive symptoms significantly predicted change in pain severity in affective (β=0.358; 95% confidence interval [CI], 0.206-0.480; P=0.006), sensory (β=0.384; 95% CI, 0.257-0.523; P=0.002), and evaluative pain (β=0.456; 95% CI, 0.285-0.605; P=0.002). The indirect effects of change in PSE partially accounted for the relationship between change in depressive symptoms and change in sensory (β=0.105; 95% CI, 0.016-0.241; P=0.023) and evaluative pain (β=0.121; 95% CI, 0.010-0.249; P=0.040). The relationship between change in depressive symptoms and change in affective pain was fully accounted for by the indirect effect of change in PSE (β=0.203; 95% CI, 0.082-0.337; P=0.002).'] Does pain self-efficacy mediate the relationship between depressive symptoms and pain severity?