Down syndrome. with an incidence of 1 in 660 live births, remains the most common human malformation pattern. Individuals with Down syndrome have an increased incidence of congenital heart disease (50%). ophthalmologic disorders 45%), gastrointstinal disorders (13%), thyroid disease (8%), and leukemia (1%). Rheumatoid disease and dementia are more frequent in older individuals with Down syndrome than in the corresponding general population. Motor development is usually delayed with Down syndrome, but motor ability at maturity is variable and exhibits a spectrum from significant functional disabilities to highly developed athletic skills. While the average IQ of studied populations with Down syndrome is 30, there are wide variations in cognitive development, from severe retardation to normal intelligence. Musculoskeletal problems commonly occur in Down syndrome and include patellofemoral instability, hip disease and instability, bunions, severe flatfeet and instability of the cervical spine. Degenerative changes of hips and knees may impair ambulation ability. Instability of the cervical spine may result in cord compromise. with serious neurologic impairment or death. Cervical spine instability associated with Down syndrome has been of concern since it was first reported by Spitzer in 1961. The association of cervical instability in Down syndrome was promulgated to the lay population through the efforts of the Special Olympics. In 1983, the Special Olympics Inc. disseminated its recommendation that every athlete with Down syndrome who planned to participate in the Special Olympics required a neurologic evaluation and radiographic examination of the cervical spine. Unfortunately. national protocols have not been established and interpretations of the Special Olympics recommendations vary significantly from state to state. Recommendations may require clinical and radiographic evaluation of the cervical spine at only one time in one state, while another state may require annual examinations and radiographs of the cervical spine before an athlete is permitted to participate.