Multiple sclerosis (MS) is the most common chronic inflammatory disease of the central nervous system and among the most com­mon causes of neurological disability in young and middle-aged adults. MS is an autoimmune disease caused by a complex interaction between genetic and environmental factors. During the last decades, great advances have been made in understanding the risk factors of MS and the diagnostic ability and treatment of the dis­ease have improved dramatically. It is of importance that doctors are made aware of the possibility of an early diagnosis and effective treatment. In this paper we discuss new knowledge regarding the etiology, diagnosis and treatment of MS.