tLess than half of all adults meet the federal exercise recommendations (CDC, 2010) and college-aged adults may be more vulnerable to the consequences of physical inactivity with about two-thirds of college students leading sedentary lifestyles (Harvey-Berino, Pope, Gold, et al., 2012; Tully & Cupples, 2011). Mobile apps provide an efficient way to track physical activity and electronic prompts can enhance mobile apps by reminding individuals to participate. Therefore, the purpose of this study was to examine the effectiveness of a mobile app and electronic prompts sent via Twitter for promoting exercise motivation and adherence in sedentary university students. The hypotheses tested were: (a) a significantly greater percentage of participants in the treatment group would progress through the stages-of-change (SOC) from pre- to post-program compared to the control group, and (b) the treatment group would demonstrate significantly greater exercise adherence than the control group. Thirteen participants followed an 8-week running program on a mobile app. The control group (n = 8) followed the running program while the treatment group (n = 5) also received electronic prompts sent via Twitter to remind participants to exercise. The SOC modified four stage algorithm was used pre- and post-program to assess exercise motivation. Exercise adherence was measured by total number of completed workouts out of the 24 prescribed. A significantly greater number of participants in the control group progressed at least one stage from pre- to post-program compared to participants in the treatment group, χ2 = 6.9, p = 0.008. Additionally, participants in the control group reported a greater number of completed workouts (M = 12.5, SD = 7.6) compared to the participants in the treatment group (M = 3.6, SD = 4.0). These findings suggest that while the mobile app may be beneficial for promoting exercise motivation and adherence, the electronic prompts sent via Twitter appeared to have no effect. Further studies are needed to determine the most effective way to use Twitter to increase exercise motivation and adherence of sedentary university students.