This textbook (Fundamentals of Biological Chemistry) attempt to fill a gap which exists in the literature. It provides a synthesis of existing knowledge on the basic chemistry of bio-molecules (carbohydrates, lipids, cholesterol, amino acids, proteins, enzymes, and nucleic acids), in addition to atomic structure, pH, buffer solutions, functions and properties of water. The unique feature of this book is that, its information is based on most recent discoveries and publications on the fore-mentioned fields and discusses the basic chemistry of all bio-molecules and related molecules all together. This helps in making biochemistry interesting and easy to understand. The book is precise, lucid, simple, interesting and authentic in its contents. I hope that, the book will be of great benefit for students of all disciplines and help them easily grasp biochemistry and doing well in the exams and for new lecturers of biochemistry who wants to refresh their knowledge in biological chemistry.