The purpose of our study was to examine the impact of mentoring-based professional development on physical education teachers' efficacy. Experienced mentor teachers were paired (n = 15) with inexperienced protege teachers (n = 15) at the beginning of a yearlong intervention study. It was hypothesized that teachers would increase their efficacy to use pedometers and computers to enhance instruction, and reduce their computer anxiety. Repeated-measures ANOVAs for mentors and proteges revealed a variety of significant main effects. We found increases in computer and pedometer efficacy. A second set of repeated-measures ANOVAs based on mentors', proteges', and control groups' scores revealed a significant interaction for computer efficacy, indicating that both mentors and proteges significantly increased their computer efficacy compared with the control group. Finally, a significant interaction effect was also found for pedometer efficacy, again indicating that both groups significantly increased their efficacy compared with control teachers. (Contains 1 table and 1 figure.)