A multiple baseline design across four behaviors was used to assess the effectiveness of a self-monitoring behavioral weight reduction program. The four behaviors were (1) the number of arm lifts used to direct food and liquid, other than water, into the mouth, (2) the number of minutes the subject engaged in daily exercise, (3a) the number of meals eaten per day, and (3b) the number of balanced meals eaten per day. The subject involved in this study was a 22-year-old male graduate student who was approximately 25 pounds overweight. At the completion of the study the subject lost a total of 19 pounds, at a rate of 1.73 pounds per week, over an eleven-week period. The results indicated that a self-monitoring behavioral weight reduction program was effective in reducing the weight in a 22-year-old male graduate student. A follow-up check six months later revealed an additional nine-pound weight loss. The study emphasized the need for reliability checkers in the natural environment to increase the dieter's adherence to weight control techniques.