Like faces, bodies are significant sources of social information. However, research suggests that infants do not develop body representation (i.e., knowledge about typical human bodies) until the second year of life, although they are sensitive to facial information much earlier. Yet, previous research only examined whether infants are sensitive to the typical arrangement of body parts. We examined whether younger infants have body knowledge of a different kind, namely the relative size of body parts. Five- and 9-month-old infants were tested for their preference between a normal versus a proportionally distorted body. Nine-month-olds exhibited a preference for the normal body when images were presented upright but not when they were inverted. Five-month-olds failed to exhibit a preference in either condition. These results indicate that infants have knowledge about human bodies by the second half of the first year of life. Moreover, given that better performance on upright than on inverted stimuli has been tied to expertise, the fact that older infants exhibited an inversion effect with body images indicates that at least some level of expertise in body processing develops by 9 months of age.