BACKGROUND: The therapeutic armamentarium for metastatic renal cell carcinoma has rapidly expanded over the past decade to include a number of anti-angiogenic therapies and more recently, an immunotherapy. Biomarkers in the peripheral circulation are easily accessible, can provide important prognostic value, and have the potential to give important information about disease progression and treatment sensitivity or response. MAIN FINDINGS: Herein, we review a variety of circulating markers including circulating protein markers (VEGF-A, inflammatory cytokines, and LDH), circulating nucleic acids (cell free DNA and micro RNAs), and circulating cellular factors (circulating tumor cells, circulating endothelial cells, and immune cell subsets). We discuss these biomarkers in the context of their ability to provide prognostic and predictive information to anti-angiogenic and immunotherapeutic agents. PRINCIPAL CONCLUSIONS: While promising, there is still much work to be done, and prospective evaluation of any potential predictive biomarker for these therapies is greatly needed.