The prevalence of obesity is rising dramatically and is strongly linked to increase in the consumption of energy dense food. Since olfactory perception represents an important element of flavor perception, the palatability of the food we consume must be heavily influenced by the olfactory system. The insulin signalling pathway is central to the metabolic syndrome. Insulin receptors are highly distributed in the central nervous system. Insulin action in the central nervous system, particularly the hypothalamus, regulates energy homeostasis and thereby influences body weight and food intake. However, the highest expression of insulin receptors were found in the olfactory bulb. Therefore, it is likely that insulin receptors in the olfactory system play a central role in energy metabolism by modulating olfaction. Indeed, studies have confirmed the ability of food-related odours to stimulate cephalic phase responses including insulin release. Still, the exact role of insulin action in the olfactory system is unclear. The overall aim of the current research proposal is to gain more insight into the specific role of insulin and its neuronal pathways in the olfactory system regulating energy homeostasis. These goals will be addressed by selective inactivation of insulin receptors in the olfactory system by conditional mutagenesis in mice.