Objective:To test the efficacy of transcranial direct current stimulation (tDCS) in addition to group exercise on non-specific chronic low back pain.Design:Double-blinded randomized control trial.Subjects:Patients with non-specific chronic low back pain.Methods:A total of 35 subjects were recruited and allocated to real- or sham-tDCS followed by a group exercise protocol. Each patient underwent five sessions of brain stimulation followed by 10 sessions of group exercise. Subjects were evaluated before and after tDCS, after group exercise and one month after the combined treatment. Outcome measures were Visual Analog Scale for pain intensity, Roland Morris Disability Questionnaire, EuroQuol-5 Dimension and Patient Health Questionnaire-9.Results:Significant between-group difference in pain intensity (−27.7 ± 30.4 mm in real-tDCS group compared to −2.2 ± 30.1 mm in sham-tDCS group) and Patient Health Questionnaire-9 (−4.9 ± 4.2 in real-tDCS group compared to −1.1 ± 2.7 in sham-tDCS group) was found one month after the combined treatment ( P < 0.05).Conclusion:Our results showed that real-tDCS can induce significant larger effects on pain and psychological well-being, compared to sham-tDCS, when it is associated with a group exercise program. The effects were observed mostly in the follow-up.