Objective: In this update on multiple sclerosis, the main clinical aspects and the basic features of the diagnosis including the new McDonald criteria, symptoms, pathophysiology, therapy and multiple sclerosis status in Saudi Arabia is discussed. Method: reviewed available diagnosis methods and therapies. Conclusion: A new McDonald criterion is useful tool for the diagnosis of multiple sclerosis. An initial symptom of multiple sclerosis is weakness in one or more limbs (40%).demyelination is the main pathophysiological event. Disease-modifying treatment focuses on the long term management of the disease with the aim to reduce relapse rates, lessen severity, and to slow the progression of disability and cognitive decline. Multiple sclerosis is not common in Saudi Arabia, it may be fairly prevalent, under-diagnosed and in increasing. there is need to educate the common community mostly rural community by awareness, attitude and knowledge about multiple sclerosis in order to enhance patient’s adherence to treatment and his/her quality of life.