Persons with spinal cord injury (PSCI) are an increasing subpopulation due mainly to advances in medicine. There were about 250,000 PSCI in the US in 2005 (NSCISC, 2005). Promoting a healthy lifestyle, especially one with physical activity (PA) participation, is critical to prevent secondary conditions and improve quality of life of PSCI. The purpose of this study was to conduct a comprehensive review on the status and critical issues in assessing PA of PSCI. Using the key words “spinal cord injury, physical activity and energy expenditure (EE),” a PubMed search was conducted. A total of 337 published studies were identified and 77 were used for this review. It was found that, while there is a growing interest in assessing PA of PSCI, only a few research studies focused on measurement issues have been published. Two critical issues emerged in the review. The first one is that resting metabolic rate (RMR) in PSCI are lower than their able-bodied counterparts so estimating EE of this population has to take this characteristic into the consideration. The lower EE of PSCI was likely caused by the lower RMR, which is due to a lower fat-free mass but higher fat mass. In addition, interruption in sympathetic nerve system activity was believed to play a major role also (Glaser, 1985; Jones et al., 2003; Monroe, 1997). The second issue is that psychometric qualities of PA measures have not been well established for this population. While many measures, such as indirect calorimetry, heart rate, diary, direct observation, movement sensors, or questionnaires (e.g., Bauman, 2004; Buchholz et al., 2003; Monroe, 1998; Washburn & Copay, 1999), have been employed to measure PA of PSCI, few of them were validated using the doubly-labeled water method, the gold standard of EE; and most reported instrument reliabilities are indeed the stability of persons' PA behaviors. Because the MET values of most of the activities engaged in by PSCI are unknown, EE estimation based on questionnaires or diaries are really questionable. Based on these finding, a discussion on how to address these issues and future research needs in assessing PA of PSCI will be presented. Keyword(s): adapted physical activity, assessment, measurement/evaluation