There is an increasing number of clinical trials testing new compounds which act at different stages of Multiple Sclerosis (MS). To prove their effectiveness several clinical outcome measures are used. The overall quality of clinical trials is increasing steadily due to the growing experience in this area, the increasing awareness of quality standards in the MS community and the more stringent requirements of regulatory authorities for approval of new treatments. Each successful clinical trial provided additional information that could be incorporated into the design of subsequent studies to improve their quality. However, the choice of appropriate outcome measures still presents major challenges. For an individual patient improvement or stability of their disability and to a lesser extent the relapse rate, are the main targets of treatment. As there is yet no scale or assessment, which objectively covers all major issues, it is recommended to use multiple instruments and endpoints as secondary outcome measures.