Background: Low back pain (LBP) is a major health and economic problem worldwide. Graded activity and physiotherapy are commonly used interventions for nonspecific low back pain. However, there is currently little evidence to support the use of one intervention over the other in the medium-term. Objective: To compare the effectiveness of graded activity exercises to physiotherapy-based exercises at mid-term (three and six months��� post intervention) in patients with chronic nonspecific LBP. Methods: Sixty-six patients were randomly allocated to two groups: graded activity group (n = 33) and physiotherapy group (n = 33). These patients received individual sessions twice a week for six weeks. Follow-up measurements were taken at three and six months. The main outcome measurements were intensity pain (Pain Numerical Rating Scale) and disability (Rolland Morris Disability Questionnaire). Results: No significant differences between groups after three and six month-follow ups were observed. Both groups showed similar outcomes for pain intensity at three months [between group differences: ���0.1 (95% confidence interval [CI] = ���1.5 to 1.2)] and six months [0.1 (95% CI = ���1.1 to 1.5)], disability at three months was [-0.6 (95% CI = ���3.4 to 2.2)] and six months [0.0 (95% CI = ���2.9 to 3.0)]. Conclusion: The results of this study suggest that graded activity and physiotherapy have similar effects in the medium-term for patients with chronic nonspecific low back pain.