The blind population is increasing rapidly and, according to the American Foundation for the Blind's report (2003), about 75,000 Americans become legally blind each year. This trend is continuing and has been observed worldwide. Since the world is designed for sighted people, moving around in the environment becomes very difficult when vision is lost. Also, blind individuals' physical activity and mobility decrease significantly resulting in a sedentary lifestyle (Longmuir & Bar-Or, 2000), which is directly related to many health risk factors. While physical activity is extremely important to the health and well-being of the blind population, little is known about physical activity patterns in this population. Questions such as, "Where do blind individuals get their physical activity?" "Which physical activity is engaged in most by blind individuals?" and "What is the most efficient way to increase the physical activity of the blind population?" have not been answered. To fully address these questions, valid and efficient measures that can detect the interaction between the blind individuals' physical activities and their surrounding environment are essential. Physical activity space (PAS), which not only measures physical activities themselves, but also identifies surrounding environmental determinants, presents a promising approach to study and understand physical activity patterns of blind individuals. With accurate information on PAS, designing more effective physical activity promotion programs and creating a physically active environment for the blind population become possible. A preliminary study has been conducted to determine the PAS of blind individuals. Using GeoLogger, a GPS device, and Armband, a multi-sensor device that records the participants' energy expenditure and steps walked, the PAS of a small group of blind individuals was studied. Some interesting physical activity patterns were observed. For example, during a common study week, a relatively new blind student showed a clear "planned physical activity behavior": Guided by a dog, he took a bus to the university and walked around the buildings where he took classes, on an almost identical path. During the weekend, in contrast, this student almost always stayed at home except for spending a very little amount of time shopping in familiar shops. After providing an introduction of some background information about physical activity research for the blind population, this presentation will focus on how PAS may help us understand the physical activity behavior of the blind population. By illustrating the findings of the preliminary study, future research topics, challenges and directions will be addressed. Keyword(s): community-based programs, measurement/evaluation, physical activity