Fifty RA patients and 50 healthy individuals have been participated in this study. 196 M/R polymorphism of TNFRII gene determined by PCR-RFLP, IL-37 level was measured by ELISA technique, also RF, ACCP, CRP measured by ELISA technique. Our study shows an increase in IL-37 levels in patients was suffered from rheumatoid arthritis relative to control group. (M=101.31+10.41) That shows major differences between patients and controls (p<0.01) and increasing level of IL-37 correlate significantly with increasing level of CRP (p<0.05). The frequencies of TNFRII gene polymorphism were significantly correlate with the IL-37 level (p<0.01) in RA patients compared with control group. In conclusion, IL-37 increased in RA patients associated with disease development, also significantly associated with TNFRII polymorphism.