Pulmonary rehabilitation is an evidence-based intervention for the management of patients with chronic obstructive pulmonary disease (COPD). In clinical practice, the 6-minute walk test (6MWT) is commonly used to assess changes in functional exercise capacity in COPD patients following pulmonary rehabilitation with the primary outcome reported being the distance walked during the test (i.e. 6MWD). The 6MWD has demonstrated validity, reliability after one familiarisation test and the capacity to detect changes following putmonary rehabilitation. In addition to assessing the outcomes of pulmonary rehabilitation, 6MWD may be used to quantify the magnitude of a patient's disability, prescribe a walking programme, identify patients likely to benefit from a rollator and to identify the presence of exercise-induced hypoxaemia. This review describes the applications of the 6MWD in patients with COPD undergoing pulmonary rehabilitation. (c) 2007 Published by Elsevier Ltd on behalf of Chartered Society of Physiotherapy.