About 49 million Americans are suffering with disability and 24 million of them have severe disability (U.S. Census, 1992). Engaging active lifestyle thus becomes critical in order to prevent the decline of fitness due to disability. To be able to accurately measure physical activities (PA) participation of this population is essential for its PA promotion. Without knowing MET values of PA engaged by individuals with disabilities, assessing PA using self-report measures becomes very difficult. Little work, however, has been conducted to determine the MET values of PA activities engaged by individuals with disabilities. So far, only one abstract was published for the METs score in individuals with spinal cord injury (Collins, Langbein, Williams, Maloney, & Nemchausky, 2002), in which the values of only eight PA of individuals with disabilities were examined. The MET scores examined were found to be different from that reported in the compendium by Ainsworth et al. (2000). For example, the MET value of doing dishes was 1.8 for the individuals with spinal cord injury, which is lower than the value MET score (2.3) reported in the compendium. Collins et al. (2002) also pointed out that many activities of individuals with disabilities had not been included in the compendium (e.g., wheel tile, wheel carpet, wheel side walk, and wheel grass). To determine the MET values of PA engaged by individuals with disabilities is not an easy task because of many different kinds of disabilities and different degree of the disability severity. Small and limited subjects could be another challenge. By reviewing the needs and current status of the research in this area, this presentation will focus on the possible solution in this area (e.g., using single-subject design; Spadone et al., 2003; or small-sample study; Maki & Langbein, 1995; Merati, Sarchi, Ferrarin, Pedotti, & Veicsteinas, 2000). Other critical issues in this area will also be addressed. Keyword(s): adapted physical activity, assessment, physical activity