The first 1,000 days of life constitute an important period for development of health and eating behavior. While the feeding mode drastically evolves, the child learns “how”, “what” and “how much” food to eat. When orally exposed, infants discover food properties, with a variety of tastes, flavors, textures, as well as energy densities. Here we focus on deciphering the involvement of taste and olfaction in the early establishment of eating behavior. In the OPALINE French birth cohort (Observatory of Food Preferences in Infants and Children), taste and flavor preferences were studied in relation with food preferences over the first 2 years. Both taste and flavor preferences evolved during this period. At weaning, a higher preference for sweet, sour and umami tastes was associated to a higher acceptance and sweet, sour- and umami-tasting foods, respectively. At 12 months, rejections of the odor of trimethylamine and of dimethyl disulfide were related to the rejection of fish and sulfurous cheeses, respectively. Further, at 20 months, food neophobia was associated to odor differential reactivity but not to taste differential reactivity, revealing the importance of olfaction in neophobic reactions. Further studies are ongoing to examine the long term effect of early taste and flavor exposure on food preferences.