Abstract Rheumatoid Arthritis(RA) a chronic disease with articular and extra-articular involvement has a multifactorial etiology. Adenosine Deaminase (ADA) is an enzyme involved in the metabolism of Purine bases. Methotrexate being successfully used as a DMARD acts through purine metabolism. It seemed justified to estimate ADA, a biomarker as a diagnostic, therapeutic and prognostic tool in RA.