Rheumatoid arthritis is complex autoimmune disorder associated with peripheral. As it is associated with immune system, cytokines and their polymorphisms are widely studied. IL-18 is a cytokine associated with many autoimmune disease. This investigation has been done to study effect of IL-18 polymorphism in pathophysiology of Rheumatoid Arthritis. PCR followed by RFLP method has been used to detect genotype and allele frequency. The pattern of genotype and allele distribution in disease and control group suggested a significant strong association of CC genotype carriage and C allele carriage (p value-0.0090*, OR-1.940 95%CI- 1.182 – 3.185 and p value-0.0074, OR-1.704, 95%CI- 1.163 – 2.498 respectively) meanwhile A allele was protective (p value- 0.0074, OR- 0.5867, 95%CI- 0.4003 – 0.8600) in RA susceptibility.