Exercise games that employ video game technology are increasing in the marketplace but have received scant research attention despite their popularity. The purpose of this study was to evaluate the effect of videobike gaming on the constructs of the theory of planned behavior (TPB) and adherence in comparison to a cycling condition where participants listen to self-selected music. Participants were 29 inactive young men assigned randomly to experimental (n = 16) or comparison (n = 13) conditions. The recommended training regime consisted of moderate intensity activity (60-75% heart rate reserve), 3 days/week for 30 min/day for 6 weeks. At the end of the first session, participants were asked to complete TPB measures and these were subsequently measured 6 weeks later. Attendance was used as the measure of adherence. Results showed that affective attitude and adherence across the 6 weeks significantly favored the videobike condition over the comparison condition. Regression analyses suggested partial mediation of the effect of the videobike condition on adherence via affective attitude. This is the first study to provide evidence that interactive videobikes may improve adherence over traditional cycling because the activity produces higher affective attitudes. The results are promising for expanding to community-based evaluation.