Walking and cognitive impairments are common in persons with multiple sclerosis (MS). Approximately 85% of persons with MS report walking as a major limitation, whereas 65% experience cognitive dysfunction. Traditionally, walking and cognition have been viewed as unrelated, but there is evidence of cognitive-motor interference (CMI). CMI is believed to stem from damage to common neural substances responsible for cognitive and motor functions. Recent evidence supports cognitive-motor interference in persons with MS. For example, there is evidence that walking performance declines when performed in conjunction with a simultaneous cognitive task (i.e., dual task cost [DTC] of walking). This decline in walking performance is greater in persons with MS compared to healthy control and is associated with walking impairment. The degree of CMI during walking is associated with walking performance and cognitive function in people with MS. For instance, CMI has been found to be related to general cognitive function and self-reported everyday cognitive errors in people with MS with minimal disability.