Rheumatoid Arthritis (RA) is a chronic inflammatory disease characterized by progressive joint inflammation that results in bony erosions and cartilage damage. Until recently only 2 genes were unambiguously correlated with disease risk: the HLA-DRB1 and the protein tyrosine phosphatase non-receptor 22 (PTPN22). Several genome wide scans conducted in populations from UK, USA and Sweden have suggested other risk loci including TNFAIP3-OLIG3, TRAF1-C5 and STAT4. The search for genetic regions associated with complex diseases such as RA is an important challenge that could lead to better diagnosis and treatment directed at the cause of the disease.