OBJECTIVES:The aim was to measure changes in walking patterns and self rated fatigue in people with multiple sclerosis (MS) compared with age matched control subjects, from the morning to the afternoon within a single day. METHODS:Fourteen patients with MS and the same number of matched control subjects performed four 10 m gait trials at their preferred walking speed at 10 00 am and then again at 3 00 pm on the same day. Gait speed, stride length, cadence, and the percentage of the gait cycle spent in double limb support were measured using a foot switch stride analyzer. Patients with MS also self rated their fatigue levels in the morning and afternoon using an 11 point scale. RESULTS:Compared with control subjects, patients walked very slowly, with reduced stride length and around twice as much variability in gait performance. Although self rated fatigue significantly increased from the morning to the afternoon, walking patterns remained consistent in both groups over the course of the day. CONCLUSIONS:These findings imply that mechanisms controlling locomotion are separate from those regulating perceived fatigue. Objective measures of performance, rather than self report, should be used to monitor change in patients with multiple sclerosis.