We conducted a cross-sectional, geographically based study of functional status in an incident cohort of 124 multiple sclerosis (MS) patients with onset of disease from 1 January 1976 to 31 December 1986 in Møre and Romsdal County, Norway. The cohort comprised 58 men (46.8%) and 66 women (53.2%). One hundred and thirteen patients (91.1%) had a primary remitting course of disease and 11 (8.9%) had primary progressive MS. The mean age of onset was 33.3 years (range 14-64), and the mean duration of disease 7.8 years (range 1-23). The Minimal Record of Disability (MRD) of multiple sclerosis was applied to measure the degree of impairment, disability and handicap. The mean Kurtzke Expanded Disability Status Scale (EDSS) score was 3.76 (0-10), and the frequency distribution of the EDSS scores in the cohort was bimodal. Twenty-eight (22.6%) patients in the cohort had marked paraparesis, paraplegia of quadriplegia. Nineteen patients (15.3%) had frequent urinary incontinence, need for almost constant catheterization, or need for constant use of measures to evacuate stools. Five patients (4%) had a severe decrease in mentation or dementia. Forty-eight patients (38.7%) reported frequent problems with fatigue or fatigability preventing sustained physical function. Less than half of the cohort (42.7%) was working full-time, and 49.2% of the patients reported that they received external support to maintain their usual financial standard. Lack of ability to work full-time and accordingly the dependence upon external financial support were significantly associated with the primary progressive course of disease. Fatigue was statistically significantly related to lack of working ability. The estimated cost of MS in the county in 1991 was 48.2 million NOK (approximately 7.531.250 US $) based on the cost-of-illness methodology.