The benefits to be gained from evaluating motor development in young children far outweigh the problems and pitfalls. As information accumulates and is replicated, a more accurate picture of the process of motor development of children is being formed. Research efforts that use a combination of longitudinal and cross-sectional approaches, that focus on both form and performance, and that recognize and need for patient, unbiased data collection are making significant contributions to our understanding of motor development. There is an ever-increasing number of published and unpublished tests purported to be measures of motor development. The vast majority of these assessment instruments are product-oriented and provide information concerning the present status of the child in a varity of areas. They are descriptive and generally establish a standard of performance based on cetain expectations for each chronological age. Product-oriented assessment instruments can be of value to the motor development specialist if they are both valid and reliable. Unfortunately, the validity of many tests is suspect because of the lack of sound rationale, or because of inadequate correlational attempts with other tests purporting to measure the same thing. Product-oriented tests may be classified as either screeing devices or behavioral assessment devices. The Denver Developmental Screening Test, and Purdue Perceptual-Motor survey are easy-to-use tools available for quick but gross classification of children. The Bruininks-Oseretsky Test of Motor Proficiency is a widely used behavioral assessment instrument for young children. There are far fewer process-oriented tests although there is a great need to know more about the developmental progression of movement skill acquisition. The Fundamental Movement Pattern Assessment Instrument and the Developmental Sequence of Fundamental Motor Skills Inventory represent two initial attempts at assessing the quality, rather than the quantity, of movement.