THE LABORATORY INVESTIGATIONS AND DIAGNOSIS OF VIRAL DISEASES represents the role of various viral diseases, the mode of their transmission from one person to another and how they get viral infections. In this textbook we have covered all the basics regarding the origin of virus, various types of viral diseases along with their mode of transmission. Virus has its own characteristic properties as compare to other microorganisms.In the numerous sections of the text we have attempted to accumulate information from many of the basic sciences for proper diagnosis and treatment of viral diseases. This approach is helpful on focusing the major aspects should be considered while diagnosing a viral disease and its certain other prospective.