The weight loss of 16 obese patients (greater than 130% ideal body weight) who participated for three months in a comprehensive, multidisciplinary weight reduction program was studied. Patients were divided into two groups based on the reported time of onset of their obesity. Childhood-onset obesity was defined in this study as marked weight gain by the age of 11. Adult-onset obesity was defined as weight gain occurring at 18 years of age or later. Each group of patients consisted of two males and six females. The childhood-onset obesity group lost significantly more weight than the adult-onset obesity group during this three-month period (19.45 +/−3.6% versus 16.17 +/−2.8%). This preliminary study suggests that patients with childhood-onset obesity tend to lose more weight in a comprehensive multidisciplinary weight reduction program than patients with adult onset obesity.