ABSTRACT:The renin-angiotensin system (RAS) plays an important role in pathogenesis of hypertension, congestive heart failure, and chronic renal failure. In addition to a discussion of the current understanding of the chemical structures and the modes of action of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor (ATR) antagonists, review includes their SAR analysis and chemical modification for improving their activity. Nowadays different modeling strategies are underway to develop tailor made molecules with the best of properties among nonpeptide renin inhibitors, dual action receptor antagonists (e.g. angiotensin and endothelin antagonists, ACE/NEP inhibitors, AT 1 /TxA 2 antagonists, balanced AT 1 /AT 2 antagonists), triple inhibitors. In the first part is given an overview of various ACE inhibitors. The second part is devoted to overview of angiotensin receptor antagonists. The advances that have been made, new opportunities, and future directions of design and development of these classes have been discussed.