This study examined the effect of a walking intervention on step counts among patients with chronic back pain who report opioid use. Data were collected as part of a randomized trial to reduce back-pain-related disability. Participants (n = 118 usual care, 111 intervention) were Veterans receiving care within one healthcare system. Step counts were collected at baseline, 6 mo, and 12 mo via an uploading pedometer. Self-reported opioid use was collected by survey. More than 40% (n = 99) of participants reported opioid use at baseline. After adjustment, the predicted mean step count for baseline opioid users assigned to the intervention increased by more than 1,200 steps compared with a reduction of nearly 400 steps for those assigned to usual care (between-group difference = 1,625 steps, p = 0.004). Among nonopioid users, there was no change for those in the intervention (-16 steps) and an increase of about 660 steps for those assigned to usual care (between-group difference = 683 steps, p = 0.17). These data show that patients taking opioids may engage in walking to help manage their back pain. This finding emphasizes the importance of encouraging the use of alternative pain management strategies for these patients.