Abstract : Mongolian people present themselves as a nomadic herder people and as meat eaters. On monographic background, the thesis presents an anthropology of food of steppes nomadic herder families and of urban settled families belonging to the same networks of relationships and socio-economic mutual aids. From a study of techniques for appropriating foods, their categorization, the culinary treatments of preparation and cooking, the distribution and consumption, the leftover foods sorting for conservation and the fate reserved to the wastes, the ordinary food practices and food practices of hospitality, as well as extra-ordinary food practices of feast (birth) and of reverse of feast (death) are analyzed. The recurrent theme of the thesis is the sharing that confers to the foods other qualities than nutritive. Cooked or raw, foods are offered to living humans, to the souls of recently deceased persons, to ancestor's manes, to the spirits masters of nature or to Buddhist divinities for receiving many blessings in return, and to the wandering souls of dead persons to avoid misfortune. The anthropological analysis suggests between the lines how three ideological systems -- the one left by Communist atheistic regime, Buddhism today's officially declared state religion and shamanism emerging as a reinterpreted form --, cohabit in the minds of families after several historical periods of confrontations and persecutions.