Objectives: Strong evidence theorizes that neurodegeneration and axonal loss in multiple sclerosis (MS) may occur independently of or may even be the cause of the demyelination in MS. The aim of this work was to assess the extent of neuronal degeneration and axonal damage in patients with relapsing remitting multiple sclerosis (RRMS) through measuring the serum level of S100B and total tau, and to evaluate the impact of treatment with interferon beta on their level.