As knowledge of pathophysiology and treatment options for multiple sclerosis has been expanding, decisions about when and which drugs we should start and switch appropriately have became important. It should be based upon individuals’ baseline clinical, environmental, demographical, and radiological biomarkers that correlate with long-term disability. In addition, a timely assessment of treatment response and adverse effect should be followed after the initial treatment. Several prognostication tools were developed and large longitudinal studies validated them. They consisted of composition of demographical factors, clinical relapse rate, relapse severity, involvement of specific functional system, magnetic resonance imaging activity and characteristic findings (gadolinium enhancement, brain atrophy, and paramagnetic rim lesion, etc.).