Numerous studies have suggested rapid weight gain following diagnosis and initial treatment of childhood craniopharyngioma (CP) due to the damage sustained by the hypothalamus. Hypothalamic lesions formed by the treatment of the tumor and/or by invasiveness of the tumor itself are known to cause intractable weight gain, known as hypothalamic obesity. In contrast, hypothalamic obesity manifested in pediatric low-grade glioma (PLGG) patients is not as prominently addressed in literature; likely due to the expansive set of histological tumor subtypes that makes generalization challenging. Specifically, there is a lack of analysis that examines the difference in treatment, endocrinopathies, and weight gain between CP and PLGG patients. The purpose of this study was to compare hypothalamic damage in subjects diagnosed with pediatric hypothalamic low-grade glioma versus subjects diagnosed with childhood craniopharyngioma. We hypothesized that CP patients will have a more rapid post diagnosis weight gain and a greater degree of obesity compared with PLGG patients due to the more invasive nature of the tumor and the aggressive surgical treatments involved. We performed a retrospective review of the clinical records of patients who received a diagnosis of childhood craniopharyngioma or pediatric low-grade glioma at Dana-Farber Cancer Institute between 1980 and 2009. We identified 45 patients, who met criteria for evaluation, 28 were previously diagnosed with childhood craniopharyngioma and 17 were diagnosed with hypothalamic pediatric low-grade glioma. We analyzed the impact of treatment, the presence of endocrinopathies, and weight gain after diagnosis. We concluded that there was no statistically significant difference in the rate or magnitude of post diagnosis weight gain, disproving our initial hypotheses.