The research on the role of cytokines in MS has gained more interest especially after the widespread clinical application of INF-b and INF-a treatments for this disease. In this review the cytokines that are proposed to have an outstanding role in the immunological and clinical course of MS have been discussed. A specific marker of activity to follow the clinical course of the disease has not been defined, yet. The intense laboratory and clinical work on the field, however, have suggested that the cytokines could be of help in following the course and planning the treatment of MS.