The current state of physical fitness in American youth is unknown. While evidence exists that obesity levels are increasing in children and youth, data on declines in physical fitness measures (i.e., cardiorespiratory and musculoskeletal fitness) are lacking. Tracking of physical fitness components has been poorly done. Surveillance of behaviors known to relate to health-related fitness (e.g., physical activity, sedentariness) and actual health-related fitness outcomes (e.g., cardiorespiratory fitness, body composition, musculoskeletal health, and, perhaps, blood lipids, cholesterol, etc.) are important to measure. Both behaviors and outcomes are important to measure--if they are not measured, people perceive them as "not" important. In this paper, the author asserts that it is time that well defined, valid measures of health-related fitness components are identified and procedures are developed that permit surveillance and tracking of physical fitness components in children and youth. Development of surveillance systems should include many interested parties, the medical profession, professional organizations (e.g., AAHPERD and ACSM), governmental agencies (e.g., PCPFS, CDC, and HHS), teachers, epidemiologists, research scientists, measurement experts, and parents. It will be difficult to arrive at the appropriate process and measures to obtain. Nonetheless, it is an important task. It is time to initiate surveillance that results in meaningful data with which to make evidenced-based decisions about fitness levels that impact curricular and health decisions. (Contains 4 tables and 4 figures.)