The olfactory sense plays an important role in food and flavor perception, and thus in our eating behavior. This chapter provides an overview of the current status of research in this field. It describes the two-way relation between subdomains of olfactory function (detection sensitivity, pleasantness; ortho- and retronasal odor exposure) and various aspects of eating behavior (appetite, food choice, intake), and discusses the difficulties in this type of research. Findings are summarized which show that metabolic status might affect odor perception and vice versa odor exposure can affect appetite. Determination and anticipation of the type of food by odor cues may tailor the preparation of the body to the specific macronutrient composition of the anticipated foods. However, this does not automatically lead to subsequent specific food intake. Eating behavior is a complex phenomenon that entails more than simple liking or wanting of foods induced by olfactory cues, rendering the need for more research to get a better grip at understanding the underlying and interacting mechanisms to be ultimately able to customize nutrition to individual needs.