Research on the interplay of cognition and mobility in old age is inherently multidisciplinary, informed by findings from life span developmental psychology, kinesiology, cognitive neuroscience, and rehabilitation sciences. Early observational work revealed strong connections between sensory and sensorimotor performance with measures of intellectual functioning. Subsequent work has revealed more specific links between measures of cognitive control and gait quality. Convergent evidence for the interdependence of cognition and mobility is seen in patient studies, wherein cognitive impairment is associated with increased frequency and risk of falling. Even in cross-sectional studies involving healthy young and older adults, the effects of aging on postural control and gait are commonly exacerbated when participants perform a motor task with a concurrent cognitive load. This motor-cognitive dual-task method assumes that cognitive and motor domains compete for common capacity, and that older adults recruit more cognitive capacity than young adults to support gait and posture. Neuroimaging techniques such as magnetic resonance imaging (MRI) have revealed associations between measures of mobility (e.g., gait velocity and postural control) and measures of brain health (e.g., gray matter volumes, cortical thickness, white matter integrity, and functional connectivity). The brain regions most often associated with aging and mobility also appear to subserve high-level cognitive functions such as executive control, attention, and working memory (e.g., dorsolateral prefrontal cortex, anterior cingulate). Portable functional neuroimaging has allowed for the examination of neural functioning during real-time walking, often in conjunction with detailed spatiotemporal measures of gait. A more recent strategy that addresses the interdependence of cognitive and motor processes in old age is cognitive remediation. Cognitive training has yielded promising improvements in balance, walking, and overall mobility status in healthy older adults, and those with age-related neurodegenerative conditions such as Parkinson’s Disease.