Objectives: To evaluate the long term effect of mobilisation with movement on disability, pain and function in subjects with symptomatic knee osteoarthritis Design: A randomised controlled trial. Setting: A general hospital Subjects: Forty adults with knee osteoarthritis (grade 1–3 Kellgren–Lawrence scale). Interventions: The experimental group received mobilisation with movement and usual care (exercise and moist heat) while the control group received usual care alone in six sessions over two weeks. Main Measures: The primary outcome was the Western Ontario McMaster University Osteoarthritis index, higher scores indicating greater disability. Pain intensity over 24 hours and during sit to stand were measured on a 10 centimetre visual analogue scale. Functional outcomes were the timed up and go test, the 12 step stair test, and knee range of motion. Patient satisfaction was measured on an 11 point numerical rating scale. Variables were evaluated blind pre- and post intervention, and at three and six months follow-up. Results: Thirty five participants completed the study. At each follow-up including six-months, significant differences were found between groups favouring those receiving mobilisation with movement for all variables except knee mobility. The primary outcome disability showed a mean difference of 7.4 points (95% confidence interval, 4.5 to 10.3) at six-months and a mean difference of 13.6 points (95% confidence interval, 9.3 to 17.9) at three-months follow-up. Conclusion: In patients with symptomatic knee osteoarthritis, the addition of mobilisation with movement provided clinically significant improvements in disability, pain, functional activities and patient satisfaction six months later.