The main types of gynecologic cancers (GCs) include ovarian, uterine (endometrial cancer and uterine sarcoma), and cervical. In spite of often being grouped together, each GC has distinct risk factors, signs and symptoms, and prognosis. Similar to other malignancies, one of the main clinical challenges in treating GCs is the cancer’s ability to develop resistance. Cancer stem cells (CSCs) have been implicated as the cause for this resistance, and therefore, by targeting them, there is the possibility of tumor regression. Cell-surface markers, such as CD24, CD44, and CD133, are commonly used in the identification of CSCs. In particular, CD133, which is a transmembrane glycoprotein, has been used either alone or in collaboration with other markers in order to identify CSCs from different solid tumors, including GCs. There is mounting evidence that CD133 might be responsible for CSC tumorigenesis, metastasis, and chemoresistance. So, by understanding the molecular biology of CD133, CSCs can be isolated and targeted as part of therapeutic strategies. In this chapter, the clinical relevance of CD133 in GCs is discussed, with a focus on the utility and limitations of using CD133 for CSC identification and therapeutic targeting.