Abstract: Obesity prevalence increases worldwide, and the risk of various correlated diseases consistently grows. Although alterations in brain structure and regional activation pattern of obese individuals were widely explored in MRI and functional MRI studies, they remain incompletely understood at the molecular level. Receptor imaging with PET has been applied in obesity studies given its in vivo access to reveal brain receptor functional alterations. This article provides an overview on the role of PET brain receptor imaging in obesity.