We evaluated an Internet-mediated, pedometer-based program to promote walking in chronic obstructive pulmonary disease (COPD). First, we assessed the accuracy of the Omron HJ-720ITC pedometer (OMRON Healthcare, Inc; Bannockburn, Illinois) in 51 persons with COPD. The Bland-Altman plot showed a median difference of 3 steps (5th and 95th quintiles, -8.0 and 145.0, respectively). We calculated percent difference = ([manual - Omron step counts]/manual step counts) x 100. Variability in percent difference occurred at the lowest usual walking speeds. At speeds <or= 0.94 m/s, the mean +/- standard deviation percent difference was 14 +/- 26%. Nevertheless, the Omron captured >80% of the manual step counts in 20 of the 23 persons with walking speed <or= 0.94 m/s. Second, we examined step counts in 24 persons with COPD who used the Omron and an Internet-mediated, 16-week walking program. At baseline, participants with COPD walked an average of 3429 +/- 1502 steps per day. Sixteen participants completed the program with an average increase in daily step count of 988 +/- 1048 steps (p = 0.002). The Omron is accurate in persons with COPD with usual walking speeds > 0.94 m/s. Accuracy is more variable at lower speeds, but the Omron captures more than 80% of manual step counts in most persons.In this preliminary study, an Internet-mediated walking program using the Omron significantly increased step counts in COPD.