Girls 6 to 19 years old have the highest rates of obesity with about thirty percent being obese in the US (Ogden et al., 2006). Researchers studying the prevention of childhood obesity are examining exergames because playing video games is popular among youth (Rideout, Foehr, & Roberts, 2010). Recent research has mainly focused on energy expenditures during exergame play (Lanningham-Foster et al., 2006; Unnithan et al., 2006; Graves et al., 2007; Maddison et al., 2007; Mellecker & McManus, 2008). Exergaming is playing video games that require players' physical exertion (Oh & Yang, 2010). This dissertation explores how a walking support group centered around the video games Pokemon HeartGold and Soulsilver affected girls' daily physical activity levels and attitudes towards physical activity. Taking a qualitative case study (Stake, 1995) approach, this study uncovered the challenges girls at risk face in their lives and how these exergames are used in the real world by providing detailed descriptions. Consistent with previous literature (Taylor et al., 2000; Neumark-Sztainer, Story, Hannan, Tharp, & Rex, 2003), social support was an important factor for building communities and promoting girl's physical activity. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]