Inclusion Criteria:
1. Subject has a diagnosis of Rheumatoid Arthritis as defined by the 1987-revised American College of Rheumatology-classification criteria and has disease duration of less than 2 years from diagnosis.
2. Subject must have been on a dose of methotrexate therapy either subcutaneously or orally administered (15-25 mg/week) for at least 3 months prior to baseline visit and has had an inadequate response to treatment defined as having a Disease Activity Score DAS28 \> 3.2 (at Screening visit).
3. Subject must also meet the following three criteria (at screening visit): at least 4 swollen joints out of 66 assessed; at least 4 tender joints out of 68 assessed; subject must have an elevated erythrocyte sedimentation rate \>/= 20 mm/1h or C-reactive protein \> upper limit of normal.
4. Subject must fulfill at least one of the following three criteria: history of rheumatoid factor positive; history of at least one erosion on X-ray or magnetic resonance imaging; history of anti-cyclic-citrullinated protein antibody positive.
Exclusion Criteria:
1. Subject has previous exposure to any biologic therapy including adalimumab.
2. Prior disease-modifying antirheumatic drugs triple therapy with methotrexate.
3. Subject has been treated with intra-articular or parenteral administration of corticosteroids in the preceding 4 weeks prior to baseline visit. Inhaled corticosteroids for stable medical conditions are allowed.
4. Subject has undergone joint surgery within the preceding two months (at joints to be assessed within the study) of Baseline.
5. Subject has a poorly controlled medical condition, such as uncontrolled diabetes, unstable heart disease, congestive heart failure, recent cerebrovascular accidents and any other condition which, in the opinion of the Investigator, would put the subject at risk by participating in the study.
