This study examined whether a team-building intervention program would positively influence participant adherence in an exercise setting. Thirteen fitness classes were randomly assigned to a team-building condition (n=6 classes) or a control condition (n=7 classes). Instructors from the team-building condition participated in a training program for team building in their classes. Instructors from the control group were neither approached nor informed of the training program. Adherence, which was monitored over a 4-week period, was assessed using measures of attendance, lateness, early departure, and withdrawal. The perception of class cohesiveness was assessed during the 8th week of class using the Group Environment Questionnaire. The team building group had significantly higher perceptions of ATG-Task than did the control group (p<.002). In terms of adherence, there were significantly fewer drop-outs and late arrivals among participants in the classes with the team-building program.