My aim is to bring out a study guide of organic chemistry for under graduate students especially for the first year B.Sc. students and those who are interested in organic chemistry, who wish to choose study guide in their careers. This will enable them to have basic and comprehensive knowledge of the reaction, mechanism, properties, stereochemistry and applications of organic compounds. This study guide is presented in a simple and lucid manner, so that those who have some background knowledge of organic chemistry can understand it well. For the sake of convenience, subject matter covered in study guide has been divided into four chapters. 1: Alkanes and Cycloalkanes. 2: Alkenes and Alkynes. 3: Alkyl halides and Aryl halides. 4: [A] Amines and Organic Compounds of nitrogen. [B] Nitroalkanes.