Most children who are congenitally deafblind are severely delayed in their communication development and many will not achieve symbolic understanding and expression. This article discusses developmental markers cited in the research literature as predictive of or facilitative of the development of symbolism. These markers include the growth toward more abstract representations, the rate of intentional communication, joint attention to objects and others, achievement of abstract play, consonantal and interactive vocalisations, distal gesture, varied early vocabulary and categories, use of varied cues for recall, object permanence, 1:1 correspondence, cause-effect, discrimination skills, and imitation. The impact of congenital deafblindness on the achievement of these milestones is presented, along with compensatory strategies to support the child's development.