A lecture notes in a simple form giving the required information may help to increase the undergraduate readers. The contents of this book are divided into three sections. The section 1 includes General bacteriology which deals with the history, microscope, sterilization, morphology of bacteria, bacterial anatomy, staining, nutrition, metabolism, genetics, classification and antimicrobial agents. The section II includes General virology which deals with the morphology, classification, cultivation, replication, genetics, physical, chemical and other properties of viruses. The section III includes General Mycology which deals with the history, classification, reproduction and cultivation of fungi. Various books and periodicals were used as reading materials to incorporate the valuable and updated information and we trust that the book will fulfill the need of the under graduate students of veterinary microbiology