Locomotion on stairs is among the most challenging and hazardous activities of daily living for older individuals. This is evidenced by the reports that stair falls account for more than 10% of fatal fall accidents. The demands that stairs place on the musculoskeletal and cardiovascular systems are compounded by the need for input from the somatosensory, visual, and vestibular systems at various stages in the task. Many of these collaborating systems deteriorate with aging, thus increasing the difficulty and risk of failure in a task that inherently involves exposure to significant danger. The task itself varies in its degree of challenge depending on many structural and environmental factors that are outside the control of the stair user. This review explores existing literature in the area of stair negotiation by older persons in an effort to define the key factors associated with difficulty and safety on stairs and to interpret these findings in the light of possible interventions that could increase stair safety. Further research is needed to ensure that current recommendations for stair design are suitable for older stair users. A Glossary of Terms is also provided.