Question: Is there a difference in the level and pattern of free-living physical activity between individuals with chronic low back pain and matched controls? Design: Observational, cross-sectional study. Participants: Fifteen individuals with chronic low back pain and fifteen healthy controls matched for age, gender, and occupation. Outcome measures: Participants wore an activity monitor for seven days. Level of physical activity was measured as time standing and walking, and number of steps averaged over a 24-hour day (midnight to midnight), day time (9.00 am - 4.00 pm), and evening time (6.00 pm - 10.00 pm), and work days versus non-work days. Pattern of physical activity was measured as number of steps and cadence during short (< 20 continuous steps), moderate (20-100 continuous steps), long (> 100-499 continuous steps), and extra long walks (≥ 500 continuous steps). Results: Over an average 24-hour day, the chronic low back pain group spent 0.7 fewer hours (95% CI 0.3 to 1.1) walking, and took 3480 fewer steps (95% CI 1754 to 5207) than the healthy controls. They took 793 fewer steps/day (95% CI -4 to 1591) during moderate walks, and 1214 fewer steps/day (95% CI 425 to 2003) during long walks, and 11 fewer steps/min (95% CI 4 to 17) during extra long walks than the healthy controls. Conclusion: Individuals with chronic low back pain have a lower level, and an altered pattern, of physical activity compared with matched controls.