The role of cholecystokinin (CCK) as a satiety factor has been extensively documented. Although most work implicate that CCK1R mediates the control of food intake, a contributing role for CCK2R in the CCK-induced satiety cannot be totally excluded. The hypothesis that CCK2R invalidation disrupts regulatory pathways with impact on feeding behavior was examined in CCK2R-/- mice. CCK2R-/- mice developed obesity that was associated with hyperphagia. Obesity was related with increased fat deposition resulting from adipocyte hypertrophy. Expression of several adipokines was dysregulated consistently with obesity. Moreover obesity was associated with disturbed glucose homeostasis as revealed by increased fasting glycemia and insulinemia, impaired glucose tolerance and hepatic insulin resistance in CCK2R-/- mice. In vitro analysis of isolated adipocytes metabolism was consistent with increased storage but preserved insulin sensitivity. Suppression of feeding and concomitant increased expression of hypothalamic pro-opiomelanocortin (POMC) following intracerebroventricular injection of gastrin into control mice demonstrates that hypothalamic CCK2 receptors mediate inhibition of food intake. Comparative analysis of hypothalamic mediators gene expression in fed knockout and control mice demonstrated overexpression of ghrelin receptors in CCK2R-/- mice indicating up-regulation of orexigenic pathways. This effect was also observed following body weight normalization indicating a causative role in the development of hyperphagia and obesity of CCK2R-/- mice. Our results give evidence that CCK2 receptor activity plays a contributing regulatory role in the control of food intake.