To better understand young children's ability to communicate about their bodies, toddlers' comprehension and production of 27 common body-part words was assessed using parental report at 20 and 30 months (n?=?64), and self-awareness was assessed using mirror self-recognition. Children at both ages comprehended more body-part words that referred to themselves than to others' bodies, and more words referring to locations that they could see on themselves than to those they could not see. Children with more advanced mirror self-recognition comprehended and produced more body-part words. These findings suggest that with age and better understanding of the self, children also possess a better understanding of the body, and they provide new information about factors that affect how young children begin to talk about their own and others' bodies. They should be useful for practitioners who need to ask children about their bodies and body parts.