The new era of discoveries, regarding development of science microbiology begun with usage of microscopes. Furthermore, with the knowledge of existence of mirobes, scientists were setting a variety of theories about them and their impact on human quality of life, which have been in the 19th century confirmed or denied. Most important theories, towards which was unrolled controversy during almost one century, the ones about spontaneous generation and about cause of diseases. They began to inquire into presence of microbes in different samples from pond water to the blood of infected animals and thereby scientists were impressed by their discoveries and at the same time, it encourage them to the next research. Microbiology reaches its peek in period from 1857. till 1910. year. This period is called „golden age“ of micorbiology, because many today known scientists acted at the time and they were rewarded with Nobel prize for their important discoveries. Robert Koch, Louis Pasteur and Alexander Fleming made the biggest contribution to development of microbiology. Only few of their discoveries are listed, like discovery of cause of contagious diseases, isolation methods and many cures and vaccines. There are a lot of cognition, methods and procedures which were discovered at the time and today are applied in medicine, biotechnology and agriculture.