Abstract – This article presents an exploratory study on older adults’ mobility. The study was based on both observations in a complex built environment (a university hospital), and on an online questionnaire distributed to people aged 50 and more. The main objective of the two studies presented in this paper was to determine the difficulties encountered by older adults when moving outdoors and indoors. A secondary objective was to investigate the resources used in order to cope with the difficulties. The results shows that the main mobility obstacles for older adults are related, firstly, to the salience of landmarks and the spatial organization of the environment and, secondly, to the age-related decline in physical, sensory and physiological abilities. Our studies show that the main resources to overcome these obstacles are landmarks and personnel support in the hospital and Internet, GPS, plans and maps outdoors.