Medical Bacteriology has Great value in Medical Science field, because bacteria is larger group of pathogenic Microorganisms. Bacteria are the most frequent group of micro-organisms present in the soil, and they constitute approximately half of the total microbial biomass. Some Bacteria has great medical importance for diseases causing and antibiotics production. Modern Bacteriology reaches into many fields of human endeavor, including the development of pharmaceutical products while medical Bacteriology deal with pathogenic bacteria, methods of diagnosis and it?s treatment. Animal diseases caused by bacteria include tuberculosis, cholera, syphilis, typhoid fever, and tetanus. Some bacteria attack the tissues directly; others produce poisonous substances called toxins. Certain bacterial diseases, e.g., tetanus, can be prevented by injection of antitoxin or of serum containing antibodies against specific bacterial antigens; immunity to some can be induced by vaccination; and certain specific bacterial parasites are killed by antibiotics. New strains of more virulent bacterial pathogens, many of them resistant to antibiotics, have emerged in recent years.