The present publication has three important parts of Dairy Chemistry. Part - 1 Physical Chemistry of Milk deals with Theory Constituents and gross composition of milk of different species and breeds of milch animals, Colloidal and Emulsion State, Physical Properties of milk, Colligative Properties of Dilute Solution, Aqueous solution of Electrolytes, Acids and bases, Oxidation-Reduction, Nuclear Chemistry and Molecular Spectroscopy. Part -2 Chemistry of Milk deals with Theory Definition and structure of milk, factors affecting composition of milk, Milk Proteins, Milk enzymes, Milk carbohydrates, Milk Lipid and Milk Salts. Part-3 Chemistry of Dairy Products deals with Chemical composition and legal standards of milk products, Cream, Butter, Ghee, Indigenous products, Chemistry of cheese, Dried Milk Products and Ice cream and Frozen Desserts. This publication will be able to meet the requirements of educationists, students and dairy/ food technologists.