Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disease characterised by the formation of multiple renal cysts that adversely affect renal function. ADPKD shows significant progression with age when complications due to hypertension are most significant. The activation of the renin-angiotensin-aldosterone system (RAAS) occurs in progressive kidney disease leading to hypertension. The RAAS system may also contribute to ADPKD progression by stimulating signalling pathways in the renal cyst cells to promote growth and deregulate epithelial transport. This mini review focuses on the contribution of the RAAS system to renal cyst enlargement and the potential for antagonists of the RAAS system to suppress cyst enlargement as well as control ADPKD-associated hypertension.