As a chronic and disabling disease, multiple sclerosis (MS) is extremely costly, both for the individual and the family, as well as far the society. Early onset, long duration and effects on employment contribute to the extensive costs related to the illness. Thus far, studies conducted in developed countries have demonstrated that direct costs, including treatment (prior to the approval of beta interferon), medical visits, hospitalization, assistance, etc., are much lower in respect to indirect costs, such as loss of income from reduction of work activity for patients and carers, which account for up to 75% of the total cost. Informal care represents a heavy burden for the families of disabled persons and little is known about the 'intangible' costs of MS, such as those related to the influence of the disease on quality of life. In addition, the cost/benefit ratio for expensive new therapies, such as beta interferon, remains to be determined.