Abstract Olfaction is the primary sensory communication mode for most mammals; social, sexual, maternal and feeding behaviours are four basic and fundamental aspects directly related to olfaction. Herein we consider these four main aspects of olfaction in a variety of mammals from the families Ungulata and Carnivora . Firstly, we provide a brief explanation on the anatomy and how olfaction is modulated. In particular, we discuss the literature in the context of recent trends in main olfactory epithelium and vomeronasal organ functions, briefly explaining the main differences between the anatomical olfactory structures of various domestic animals. Subsequently, examples of animal welfare implications of diet selection, predation, aversion, breeding and mother-young bonding behaviours are described. An ethological view of olfaction in addition to the brain structure and olfaction morphology aspects has been covered, as it offers a promising approach in the welfare of mammalian species under our care. We conclude that the knowledge of the roles played by olfaction in chemical communication may help improving housing conditions, fulfilment of feeding requirements, handling and breeding of companion, farm and zoo mammals, and promote the development of appropriate social, sexual, parental and feeding behaviours thus enhancing animal welfare.