Objective: To examine the aerobic intensity level and pacing pattern during the 6-min walk test (6MWT) in persons with multiple sclerosis, taking into account time of day, fatigue, disability level and multiple sclerosis subtype. Design: Cross-sectional study. Subjects/patients: Eighty multiple sclerosis patients (Expanded Disability Status Scale, EDSS ≤ 6.5). Methods: Participants performed the 6MWT at 3 different time-points (morning, noon, afternoon) during 1 day. Heart rate and pacing strategy (distance covered every minute) were registered. A sub-group analysis determined the effects of fatigue, disability level and multiple sclerosis subtype. Results: The relative aerobic intensity was constant throughout the day (67 ± 10% of estimated maximal heart rate). In all sub-groups heart rate increased and distance walked declined after the first minute (p