Rheumatoid arthritis (RA) is an autoimmune disease with increasing activity of T lymphocytes and abnormal production of inflammatory cytokines. Interleukin-27 (IL-27), a multifunction cytokine with contradictory inflammatory effect. Polymorphism of IL-27 was reported to be predisposed to many inflammatory diseases and autoimmune diseases. We aimed to assess the role of IL-27 polymorphism in the predisposition of RA in Egyptian population. A case control study included 100 patients with RA and 100 healthy subjects represented the control group. The IL-27−924A/G gene polymorphism was investigated by RFLP-PCR. The serum level of IL-27was estimated by enzyme-linked immunosorbent assay. The AA genotype was significantly higher in patients with rheumatoid arthritis as compared with the control group (P=0.02, OR (95% CI)=0.4 (0.1-1.2). In addition, we observed significant elevation in the level of serum IL-27 in the patients group in comparison with the healthy subjects. We found that patients with AA genotype or A allele had significant higher level of serum IL-27. There was positive relationship between the serum level of IL-27 and severity of the disease. It was concluded that AA genotype of IL-27 gene might be a risk factor for the incidence of RA in Egyptian population. Patient with significantly higher blood levels of IL-27 were at risk for increasing disease activity.