BACKGROUND AND PURPOSE: Walking is an important functional activity and the shuttle walking test has been shown to be a useful test for patients with chronic airways obstruction and heart failure. The test has been used in low back pain research over recent years and has increasingly been used as an outcome measure to investigate treatment efficacy in patients with low back pain. The aim of the present study was to determine the reliability and responsiveness of the shuttle walking test within a group of patients with low back pain (with or without sciatica). METHOD: Reliability of the shuttle walking test was determined on a group of patients with low back pain (n = 44) using the Bland and Altman (1986) limits of agreement and the intraclass correlation coefficient (ICC). Responsiveness was assessed using the standardized effect size. The mean distance walked within a patient population (n = 337) was compared with an age- and sex-matched group of healthy subjects (n = 122). RESULTS: The shuttle walking test obtained an ICC score of 0.99, whereas the limits of agreement test gave a mean difference of 2.5 m with upper and lower limits of agreement of 52 m and -47 m, respectively. Patients undertaking fitness training reached an effect size of 1.2 compared to a control group of 0.23 and 0.94 for a group undergoing various orthopaedic treatments. CONCLUSIONS: The present study has shown that the shuttle walking test is a reliable and responsive test within a group of patients with low back pain, with or without sciatica. It is simple to administer and provides a quick method of measuring one aspect of a patient's physical function.