Introduction: Multiple sclerosis (MS) is an autoimmune, inflammatory, demyelinating neurodegenerative disease progressing with attacks. Alpha-synuclein (alpha-Syn), a neuronal protein, has been previously associated with the inflammation and development of neurodegenerative diseases. Although the cause of neurodegeneration in multiple sclerosis is mainly associated with inflammation, alpha-Syn may play a role in the pathogenesis of MS, as in other classical neurodegenerative diseases such as synucleinopathies. In multiple sclerosis, alpha-Syn has been directly studied in central nervous system lesions and cerebrospinal fluid (CSF). However, there are few studies approaching variations in peripheral alpha-Syn in MS. The aim of our study was to investigate the correlation between disease progression and other clinical parameters by measuring serum alpha-Syn and oligomer alpha-Syn levels in MS patients.