Background: The American Heart Association has created an Official 2012 Hands-Only CPR Instructional Video that is approximately one minute in length and has been viewed over 600,000 times on YouTube. Objective: To evaluate the video's effectiveness in teaching adolescents aged 12-17 hands-only CPR. Methodology: The study took place in the Phoenix metropolitan area. Study participants were recruited from high schools, junior high schools and the Tempe Boys & Girls Club. The 100 study participants took a short, four question survey and watched video on either a laptop computer or video projector. Participants were then subjected to a cardiac arrest mock scenario in which they were tested on calling 911, compression rate, compression depth, and hand placement using a Lifeform CPArlene Recording Manikin. In analysis of the data, subjects were separated into four groups: 12-14 year olds (middle school aged) who had previous CPR training (MSG-T), 12-14 year olds with no previous training (MSG-U), 15-17 year olds (high school aged) who had previous training (HSG-T) and 15-17 year olds with no previous training (HSG-U). Results: Every study participant performed hands-only CPR during the mock scenario. Between the two middle school-aged groups, the MSG-U was more likely to call 911 during the mock scenario (P<0.05). There were no significant differences in compression rate and depth between the MSG-U and MSG-T. Between the two high school-aged groups, the HSG-T was more likely to call 911 during the mock scenario (P<0.05). There was no significant difference in compression rate between the HSG-T and HSG-U groups. The HSG-T compressed the chest significantly deeper than the HSG-U group (P<0.05). The HSG-T was the only group to statistically be on par with the AHA recommended 100 compressions/minute (P<0.05). All other groups were significantly below the 100 compressions/minute standard. No groups were statistically on par with the AHA recommended compression depth of two inches. Conclusion: The Official 2012 Hands-Only Instructional Video should not be used as a definitive training tool to teach school-aged adolescents hands-only CPR. This video, as well as other similar training videos, would be useful as introductory tools for children 12-14 years of age or as a refresher for older children who have received previous training.