The book Principles of Organic Medicinal Chemistry describes the principles and concepts of chemistry, synthetic schemes, structure activity relationships, mechanism of action and clinical uses of carbon compounds in the light of modern trends. The book covers the syllabi of B.Pharmacy and M.Pharmacy courses of all Indian Universities. This book comprises of 22 chapters. Chapter 1 gives an introduction to medicinal chemistry, Chapter 2 explain about the basics on principles of drug action and physicochemical properties of organic medicinal, substances are elaborated in Chapter 3. The concepts of Prodrugs and Drug metabolism are summarized in Chapter 4 and Chapter 5 respectively. Chapter 6 to Chapter 22 explains chemistry, properties, mechanism of action, structure activity relationships, chemistry of newer drugs and clinical uses of various therapeutic agents. At the end of book, a set of more than 200 essays and short questions and 225 objective questions with answers are strategically designed.