Patients with glioblastoma (GB), a highly aggressive brain tumor, have a median survival of 14.6 months following neurosurgical resection with adjuvant chemoradiotherapy. Quiescent GB cancer stem cells (CSCs) invariably cause local recurrence. These GB CSCs that can be identified by embryonic stem cell markers express components of the renin-angiotensin system and are associated with circulating CSCs. Despite the presence of circulating CSCs, GB rarely develops distant metastasis outside the central nervous system. This paper reviews the current literature on GB growth inhibition in relation to CSCs, circulating CSCs, the RAS and the novel therapeutic approach by repurposing drugs that target the renin-angiotensin system to improve overall symptom-free survival and maintain quality of life.