OBJECTIVES: This study aims to investigate the effect of physical therapy modalities on pain and functional status in patients with non-specific low back pain. PATIENTS AND METHODS: Between February 2011 and August 2013, a total of 104 patients (38 males, 66 females; mean age 49.3±12.5 years; range 34 to 62 years) with non-specific chronic low back pain for more than 12 weeks without any neurological deficit were included in this randomized-controlled study. The patients were divided into two groups: physical therapy group (n=52) and control group (n=52). Both groups were given exercise and medical treatment; physiotherapy modalities were also applied in the physical therapy group. The patients were assessed using the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Istanbul Low Back Pain Disability Index (ILBP) before treatment and at two weeks, three months, and one year after treatment. RESULTS: A total of 100 patients completed one-year follow-up. In both groups, the VAS, ODI, and ILBP significantly improved after treatment (p<0.01), compared to before treatment values. There were statistically significant differences in the VAS, ODI, and ILBP scores at three months and one year after treatment between the physical therapy group and control group (p<0.05). CONCLUSION: Multidisciplinary approaches including physical therapy should be implemented to provide long-term improvement in pain and functional status in the treatment of non-specific chronic low back pain.