Cancer stem cells (CSCs) are a specific type of cancer cell that can both self-renew and differentiate, playing a key role in cancer development and progression. Existing clinical biomarkers, however, are insufficient as robust biomarkers to be used in clinical practice for cancer patients due to their limited confirmation and contested prognostic relevance. Therefore, there is a large pool of potential biomarkers that have not been thoroughly explored. CSC surface biomarkers have recently been the focus of many studies in the clinical practice of cancer patients due to their potential utility in characterising the aetiology of cancer initiation, development, and metastasis. In this chapter, we discuss the most popular surface biomarkers of CSCs and provide their potential utility in cancer diagnosis and prognosis.