Introduction. There is a clear lack of assessment tests for students with disability over the age of 10 years. While it is imperative that students are assessed formally throughout their school years the lack of assessments hinders true assessment of student progress grades 5 through 12. This gap in assessment must be attended in order to better serve the needs of students with disability. Methods. The aim of this study was to assess the item reliability and construct validity of the Advanced Motor Skills Test. Participants of the study were 880 public school students ages 10 to 14 years from a large metropolitan school district. The purpose of the instrument is to assess mature motor skills in students ages 10 to 14 years. Institutional Review Board and school district approval was obtained to videotape students performing a series of movement skills. Both student and parent read and signed Informed Consent. Movement skills performed by the students include: running 15 yards, grapevine for 15 yards, standing long jump, stationary basketball dribbling, basketball dribbling 15 yards, throwing tennis balls, catching tennis balls, and kicking a soccer ball. Each movement skill was performed according to established procedures with the same equipment and order of events. Results. Factor analyses were conducted in order to evaluate the dimensions of the factor structures and reliability and validity coefficients for scores on the scales and individual items. Cronbach alpha for the eight skills ranged from .88 to .96. Two clear factors (locomotor and object control) emerged supporting the inclusion of the various skills. There was an inverse correlation between locomotor and object control skills (-.41, p< .001) suggesting that the two dimensions are independent. Discussion. The results of the factor analysis support the validity of the Advanced Motor Skills Test and its use in assessing students for motor skills performance. Subsequent work will develop normative data tables and accompanying curriculum materials. The use of this test in assessing students with disability will narrow the gap in this critical area.Keyword(s): adapted physical activity, assessment, research