Interleukin-1β is a pro-inflammatory cytokine that has been involved in neuronal injury of multiple sclerosis (MS). This study was designed to assess the relation between interleukin 1 (specifically, serum level of Interleukin-1β), also its gene polymorphism T-511C and relapsing remitting multiple sclerosis. There was a highly significant difference in serum level of IL1β (being higher) between relapsing remitting multiple sclerosis patients during and in between the attacks and control subjects. IL1β gene polymorphism T-511C did not increase the risk of multiple sclerosis with no statistical difference in its distribution in MS patients and control subjects.