Introduction: Chronic nonspecific low back pain is an extremely common musculoskeletal disorder, characterized by pain, functional disability and fear of movement. Rehabilitation approaches such as core stabilization and graded activity programs are frequently prescribed, however the comparison of their effectiveness in physical and psychological measures has clinical significance. The objective of this study was to compare the effects of core stabilization exercises versus a graded activity program on the pain levels, functional disability and fear of movement in chronic nonspecific low back pain patients. Methods: The study was carried out as a single-blind randomized controlled trial for 12 weeks. The patients who met the criteria were randomly allocated into two groups; Group A, performing core stabilization exercises (n=15) or Group B, performing a graded activity program (n=15). Pain was measured by Visual Analogue Scale (VAS), functional disability by the Oswestry Disability Index (ODI) and fear of movement by the Tampa Scale of Kinesiophobia (TSK). Patients were evaluated pre- and post- intervention. Data were analyzed by paired t-test and independent t-test at p<0.05. Results: There were significant changes within the groups for the VAS, ODI and TSK in both Group A and B (p<0.001). In between-group comparisons, there was a significantly higher decrease in pain and disability in the core stabilization group (VAS: 3.67+/-0.72 vs. 5.07+/-0.70 and ODI: 31.93+/-4.07 vs. 36.87+/-4.51) while significantly higher decrease in fear of movement occurred in the graded activity group (TSK: 29.53+/-3.23 vs. 36.53+/-3.83). Conclusion: The core stabilization exercises were better than graded activity in improving pain and disability levels in patients with chronic nonspecific low back pain while graded activity resulted in better improvement in kinesiophobia. A combination of core stabilization and graded activity would be beneficial for patients with chronic nonspecific low back pain.