The identification and adoption of diagnostic and prognostic biomarkers for rheumatoid arthritis has informed and improved the clinical management of this disease. With the advent of biologic treatments such as anti-Tumour Necrosis Factor (anti-TNF) therapy, achieving disease remission has become a realistic endpoint for clinicians. The life-changing efficacy of these therapies however is restricted to the 60-70% of patients who respond. The immune reaction to anti-inflammatory therapy is thought to be influenced by many genes which cumulatively contribute to athreshold for response. There is an inherent clinical need to provide theranostic biomarkers which could determine treatment outcome. The current role of genetic biomarkers in diagnosis, prognosis and predicting response to anti-TNF therapy are discussed.