OBJECTIVE: To determine whether differences could be detected in mobility outcomes during community mobility and home mobility tasks according to type of mobility assistive device. DESIGN: Randomized, repeated measures. SETTING: Community mobility task: traversing 341.4m between the rehabilitation clinic and hospital entrance; home mobility task: traversing 39m into and out of a patient training bathroom and bedroom. PARTICIPANTS: Community-dwelling, cognitively intact ambulatory veterans (N=59) who used a mobility device within the 14 days prior to the study. INTERVENTIONS: Participants tested 3 types of mobility assistive devices with wheels: 4-wheeled walker (WW), manual wheelchair (MWC), and powered wheelchair (PWC). The first and last devices used by each participant were randomly assigned as either MWC or WW. The PWC was always the second device. MAIN OUTCOMES MEASURES: Speed (m/s), collisions (total), fatigue (0-10 Likert scale), and pain (0-10 Likert scale, diagram). RESULTS: The community mobility task was performed with all 3 devices by 52 (88%) veterans, and the home mobility task was performed with all 3 devices by 53 (90%) participants. In each task, 28 participants used the WW and 28 participants used the MWC as the final device. In the community mobility task, statistically significant differences (P<.05) were seen with ≥1 device comparison for all studied outcomes (eg, standardized mean difference for the MWC compared with the PWC showed -.67 fewer collisions for the MWC). In the home mobility task, speed, collisions, and fatigue showed statistically significant (P<.05) device-related differences (eg, standardized mean difference for the WW compared with the MWC showed -.88 fewer collisions for the WW). CONCLUSIONS: We found statistically significant and substantively different effects from 3 commonly used mobility assistive devices with wheels on diverse mobility outcomes when used in typical community mobility and home mobility tasks, providing proof of concept support for a research methodology applicable to comparative outcome studies of diverse mobility aids.