OBJECTIVE Activity monitoring is considered a highly relevant outcome measure of respiratory rehabilitation. This study aimed to assess the usefulness of a new accelerometric method for characterization of walking activity during a 3-week inpatient rehabilitation program. METHODS After individual calibration of the accelerometer at different walking speeds, whole-day physical activity was recorded for 15 patients with chronic obstructive pulmonary disease on the first and the last days of the program, and for 10 healthy subjects. Data were expressed as percentage of time spent in inactivity, low level activity, and medium level activity, with the latter corresponding to usual walking speed. RESULTS The patients spent more time being inactive and less time walking than healthy subjects. At the end of the rehabilitation program, medium level activity had increased from 4% to 7% of total recording time. However, the change was not significant after periods of imposed exercise training were excluded. Walking activity increased to a greater degree among the patients with preserved limb muscle strength at entry to the program. Although health status scores improved, the changes did not correlate with the changes in walking activity. CONCLUSIONS The findings lead to the conclusion that this new accelerometric method provides detailed analysis of walking activity during respiratory rehabilitation and may represent an additional useful measure of outcome.