Background and Purpose: The prevalence of childhood obesity is of increasing concern with the rate of obesity doubling over the last two decades. A significant decrease in the level of physical activity is considered to be one of the contributing factors. The purpose of this six week study was to evaluate the effects of a daily walking program and a change in high calorie beverage intake on the BMI of adolescent females. Subjects: Twenty-four healthy middle school girls, ages 12-14, with a BMI of 25 or greater participated in the study. Method: This study was a pretest-posttest design with subjects randomly assigned to one of two experimental groups. Each subject in group A was provided with a step-counting pedometer and encouraged to increase their daily walking to 10,000 steps per day. Beverage intake was restricted to low calorie drinks with the exception of milk. Group B followed the same walking program without the changes in beverage intake. BMI was calculated for pretest and posttest measurements. Weekly meetings were held for motivational and instructional purposes. Subjects completed self-reported data sheets. Results: Pretest to posttest change in mean BMI for all subjects (n=22) was -.37 and significant (p=0.0391). The group with the beverage restriction (n=12) had a mean BMI decrease of .23 (p=0.1913) and the group without beverage restriction (n=10) had a decrease of .55 (p=0.1212). Fourteen out of 22 subjects completing the study had a decrease in their BMI. Conclusion and Discussion: Based on our results for this six week study, a daily walking program in the absence of any other lifestyle change may decrease the BMI of overweight or risk for overweight 12-14 year old girls. A statistically significant reduction in BMI was evident across all subjects. However, there was no statistical difference between the two experimental groups. This may be due to small sample size and also that several subjects experienced a weight gain, likely skewing the results. Through discussion with the subjects and their physical education instructors, a positive shift was noted on the attitude toward walking as a means of physical activity both in and out of school. This generally sedentary population of girls, when offered the option of walking during PE, chose that versus the previous practice of non-participation. The question as to whether these results could be generalized to overweight middle and high school girls and boys warrants further study.