Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) and a common cause of disability in young adults; it is most likely an autoimmune disease. Typically, MS initially follows a relapsing-remitting course, but most patients eventually develop secondary progressive MS, where there is progressive deterioration without relapses or remissions; in some patients, MS has a primary progressive course. The diagnosis of MS requires evidence of CNS lesions disseminated in time and place, as well as the exclusion of other likely causes of these lesions; the clinical history, neurological examination and investigations, such as magnetic resonance imaging of the brain and spinal cord, all have key roles in the diagnosis. Education and counselling of the patient and family members are essential for good patient management. Moderate to severe attacks of MS are best treated with intravenous infusions of high-dose methylprednisolone. Interferon beta reduces the frequency of attacks and the progression of disability in relapsing-remitting MS. Symptomatic therapy is important in the management of spasticity, pain, urinary problems and the other symptoms or complications of MS.