In the past two year, since the Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity (USDHHS, 2001), much attention has been placed on the prevalence of obesity nationwide. Physical activity and sedentary behavior patterns have been identified as possible constraints relating to obesity in youth (USDHHS, 2001). With children spending 4.5 hours · day-1 inactive at school and an additional 5.2 hours · day-1 inactive at home (Strauss et al., 2001), focusing on physical activity alone is insufficient. Research needs to address the multifaceted nature of creating physical activity behavior change. The purposes of this interdisciplinary intervention pilot project was to 1) compare a curriculum designed to reduce media use and sedentary behavior to a traditional curriculum, 2) determine if a reduction in media use results in reduction of sedentary behaviors, 3) if the use of an interdisciplinary approach improves adherence rates to behavior change in adolescents, and 4) assess the efficacy of assessment tools in this population. This intervention program combined health education and physical education classes to reduce sedentary behavior (media use) and decrease leisure time physical inactivity in middle school adolescents. A seven-day unit was administered in the health education classes to reduce media use and in physical education to decrease sedentary behavior through student-centered teaching. Seven-day media use recall, physical activity recall, stages of change questionnaire, and demographic information (height, weight, BMI, sex, PACER score) were collected on approximately 100, 7th grade students. Chi-squared analysis was used to compare differences at post-test between the intervention group and the control group. No significant changes were observed between groups. To assess the efficacy of the surveys used in this study the reliability coefficient for each of the surveys was calculated from a control group. The Media Use survey (n = 35) produced an average alpha coefficient of 0.84. The Physical Activity Questionnaire (n = 38) produced an average alpha coefficient of 0.69. The Stage of Change questionnaire (n = 67) produced an interclass correlation coefficient of 0.93. While significant group differences were not observed in reduction of media use or sedentary behavior, data trends suggest that combining Health Education and Physical Education may be a useful strategy in changing leisure time choices in adolescents. In addition, a seven-day Media use recall and Stages of Change questionnaire are reliable in this population. Using the activity questions from the PAQ may be advantageous.Keyword(s): interdisciplinary, middle school issues, physical activity