Craniofacial microsomia (CFM) is a complex, congenital condition associated with underdevelopment of the facial structures. This condition is frequently associated with malformations of the outer, inner and middle ear, mandible, soft tissue, and facial nerve, resulting in varying degrees of facial asymmetry. As a result, children with CFM have elevated risk of hearing loss, impaired speech production, neurodevelopmental delays, poor academic and social outcomes, and behavioral maladjustment. Our prior studies in school-age children with CFM demonstrate that children with CFM do not perform as well on neuropsychological and social outcome assessments as children without craniofacial conditions. However, no studies have been performed in infants and toddlers and nor have the specific mechanisms contributing to these outcomes been investigated. The long term goals of our research consortium are to improve neurodevelopmental, social, and behavioral outcomes for children with CFM. The proposed research includes a longitudinal cohort study in children with and without CFM. The rationale underlying the research plan is that better understanding of the direct and indirect effects of CFM malformations on development will lead to the identification of more specific and effective early interventions. This proposal outlines a multi-center, longitudinal cohort study of 125 infants with CFM and 100 infants without craniofacial anomalies. Participants will undergo a series of evaluations between ages 0-3 years of age to comprehensively evaluate the developmental status of infants and toddlers with CFM. This research design will also explore specific pathways by which CFM may lead to certain outcomes. Specifically, the proposal explores (1) the longitudinal relations between facial asymmetry and emotion-related facial movements and poor socialization; and (2) associations among ear malformations, hearing and speech deficits and neurobehavioral outcomes. Results of this research will ultimately lead to future investigations that assess new interventions and corresponding changes in current standards of care for children with CFM.