In the present study, we have investigated the association of specific polymorphisms of the interleukin (IL)-1beta and IL-1 receptor antagonist (ra) gene with both the susceptibility to and the clinical characteristics of multiple sclerosis (MS) in Japanese patients. We collected and analyzed DNA from 98 MS patients and 104 healthy controls for distribution of IL-1beta or IL-1ra polymorphisms. Our results show no significant differences in the distribution of the polymorphisms between MS patients and controls. Furthermore, no association was observed between IL-1beta or IL-1ra polymorphisms and clinical characteristics, such as age at disease onset, clinical course and severity. Together, our findings suggest that IL-1beta or IL-1ra gene polymorphisms may not be relevant in the susceptibility to MS or the clinical characteristics of Japanese patients with MS.