Robert Koch (1843-1910) received the Nobel Prize in Medicine in 1905 for his studies of tuberculosis. He contributed significantly to microbiology, isolating also cholera and anthrax pathogens, and introducing several postulates in this field. In addition, he developed staining methods, as well as culturing and microscopic techniques. Many of his achievements have also influenced dermatology. This contribution reviews his life and major achievements on the occasion of the 171st anniversary of his birth.