Attempting to measure the impact of multiple sclerosis (MS) on the individuals patients has become a major issue stimulated by both the emergence of new therapeutic agents and the increasing demand to incorporate the patient's perspective. Disability has been the main focus. Recently, new disability scales have been developed and generic scales evaluated in an attempt to replace or complement the constantly used and much criticized Expanded Disability Status Scale (EDSS). There is, however, the growing realization that it is important to incorporate broader aspects of disease input such as are contained within the concepts of health-related quality of life. Current scales in this area are limited in either their scientific soundness and/or clinical usefulness, and it may be appropriate to consider the development of a new MS-specific measure of disease impact for use in clinical trials.