10.22376/ijpbs.2019.10.1.p1-12 Volume 1 Issue 3 2010 (July - September) Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by a gradual decline in memory associated with shrinkage of brain tissue, with localized loss of neurons mainly in the hippocampus and basal forebrain and also diminished level of central cholinergic neurotransmitter-Acetylcholine. Renin Angiotensin and Aldosterone system plays a major role in progression of many diseases such as hypertension, atherosclerosis, kidney failure etc., Angiotensin IV (Ang IV) is a derivative of the potent vasoconstrictor Angiotensin II (Ang II). Angiotensin receptor blockers mainly blocks AT lessThan sub greaterThan 1 lessThan /sub greaterThan receptor of Ang II because it has more affinity towards AT lessThan sub greaterThan 1 lessThan /sub greaterThan receptor. Hence this prevents action of Ang II on AT lessThan sub greaterThan 1 lessThan /sub greaterThan receptor and enhances the formation Ang IV and it has been proved for its memory enhancing property. In this work memory enhancing activity of Angiotensin Antagonists Losartan, Irbesartan and Valsartan was evaluated using Hebb's William maze (Rectangular maze) and the results shows significant increase in memory ,which is comparable between groups p lessThan 0.01.The memory enhancing capacity of the drugs were very significant when compared to normal control and negative control (p lessThan 0.001). S. Indumathy,S. Kavimani,K. V. Raman Ang II, Ang IV, Losartan, Irbesartan, Valsartan and Acetylcholine -