In the present study, the effect of attentional bias modification (ABM) on older outpatients, with chronic low back pain, was examined. This was a single-center, randomized, single-blinded, crossover trial and patients were randomly divided in a 1:1 allocation ratio into two groups: an ABM Leading group and an ABM Trailing group. Forty-three outpatients with chronic low back pain participated. Patients were evaluated four times and the treatments were ABM + Normal intervention or Normal intervention only. Outcome measures included pain intensity on the Numerical Rating Scale, the Pain Catastrophizing Scale, Fear-Avoidance Beliefs Questionnaire, Hospital Anxiety and Depression Scale, Somatic Symptom Scale-8, and EuroQol 5 Dimension-3 levels questionnaire. In addition, we performed the 30-second Chair-Stand test and the Timed Up & Go test for physical function evaluations. There was no change in pain intensity due to ABM. However, the total Pain Catastrophizing Scale score was significantly decreased, and the EuroQol 5 Dimension-3 levels questionnaire and 30-second chair-stand test were significantly improved (P <.05). The Health Science Ethics Committee, Graduate School of Biomedical Sciences, Nagasaki University (permit number: 17060861), and the clinical trial was registered with UMIN (UMIN000029424).