This self-directed learning module addresses core concepts in the assessment of any child with disability, including physical growth and development, evolution of reflexes, and cognitive and personality development. It is a section of the chapter on pediatric rehabilitation for the Self-Directed Medical Knowledge Program Study Guide for practitioners and trainees in physical medicine and rehabilitation. The rehabilitation perspective is emphasized, especially as it changes to accommodate the developing child, with a focus on specific chronic disorders such as respiratory disease, congenital heart disease, and malignancy. These types of disorders serve as a model for the management of problems that require special medical, rehabilitative, and psychosocial consideration.