The document presents a proposed definition and classification of cerebral palsy (CP) as of April 2005. The introduction highlights the need for a revised definition and classification due to advancements in neurobiology, epidemiology, and brain imaging. The definition of CP is updated to emphasize that it is a group of disorders of movement and posture caused by non-progressive disturbances in the developing fetal or infant brain, often accompanied by disturbances in sensation, cognition, communication, perception, behavior, and/or seizure disorders. The classification of CP is detailed into four major dimensions: motor abnormalities, associated impairments, anatomic and radiological findings, and causation and timing. Motor abnormalities are categorized based on the nature and typology of the motor disorder and functional motor abilities. Associated impairments include seizure disorders, hearing and visual problems, cognitive and attentional deficits, and emotional and behavioral issues. Anatomic and radiological findings specify the distribution and extent of the motor disorder. Causation and timing consider the interaction of multiple risk factors and the timing of the insult. The document aims to provide a comprehensive and multidimensional approach to CP, emphasizing the need for a standardized classification system to improve understanding, management, and research. It invites comments and feedback to further refine the proposed definition and classification.The document presents a proposed definition and classification of cerebral palsy (CP) as of April 2005. The introduction highlights the need for a revised definition and classification due to advancements in neurobiology, epidemiology, and brain imaging. The definition of CP is updated to emphasize that it is a group of disorders of movement and posture caused by non-progressive disturbances in the developing fetal or infant brain, often accompanied by disturbances in sensation, cognition, communication, perception, behavior, and/or seizure disorders. The classification of CP is detailed into four major dimensions: motor abnormalities, associated impairments, anatomic and radiological findings, and causation and timing. Motor abnormalities are categorized based on the nature and typology of the motor disorder and functional motor abilities. Associated impairments include seizure disorders, hearing and visual problems, cognitive and attentional deficits, and emotional and behavioral issues. Anatomic and radiological findings specify the distribution and extent of the motor disorder. Causation and timing consider the interaction of multiple risk factors and the timing of the insult. The document aims to provide a comprehensive and multidimensional approach to CP, emphasizing the need for a standardized classification system to improve understanding, management, and research. It invites comments and feedback to further refine the proposed definition and classification.