The habit of sucking is the first coordinated muscular activity of the infant. There are essentially two forms of sucking: the nutritive form which provides essential nutrients, while non-nutritive sucking insures a feeling of warmth and a sense of security. This review gives a description of the anatomy and physiology of sucking together with the influence of breastfeeding and bottle-feeding (conventional or orthodontic nipples) on the dentofacial structures of the infant. Factors involved in the choice of feeding are also discussed. Children who do not have access to unrestricted breastfeeding or bottle-fed children may satisfy their instinctive sucking urge with a pacifier. This paper presents the different types of pacifiers (conventional or orthodontic) along with the beneficial effects provided by pacifiers. Detrimental effects caused by incorrect use of pacifiers or digit-sucking habits are also summarized. Health professionals should inform expectant mothers about the dentofacial advantages of breastfeeding.