This review briefly recapitulates the existing markers predictive of RA responsiveness to treatment, focusing on MTX alone or combined with a biologic. In addition to the demographic and clinical factors, an update is provided of the predictive biomarkers identified by large-scale gene and protein analyses that generated new insights into the ability of high-throughput analysis of biological systems to select new potential indicators. Among the large-scale analysis tools now available, pharmacogenetics and pharmacogenomics (including transcriptomic and proteomic approaches) have been shown to provide such new putative biomarkers of therapeutic responses.