The first UW Bacteriology class taught in 1881-83 by Professor William Trelease, who incorporated bacteriology into the general botany course. This is believed to be the first bacteriology class taught at any American university. Professor Edward Birge (Botany) organized the first formal course in bacteriology in 1886. Before the College of Agriculture was established, early bacteriologists were housed in Agriculture Hall, later renamed South Hall. The first bacteriology professor was Harry Russell, who joined the university faculty in 1893. In 1889 the College of Agriculture was established, and in 1903, when the new Agriculture Hall was built, university bacteriologists moved there. Early bacteriologists include Russell, Edwin G Hastings (1898), and W. D. Frost (1895). In 1907 Russell became Dean of the College of Agriculture.
In 1914 the Department of Agricultural Bacteriology was formally established with E. G. Hastings as the first chair. In 1913 E. B. Fred was hired in the College and began the legacy that made UW a world leader in the study of biological nitrogen fixation. In 1934 E. B. Fred was made dean of the Graduate School, and in 1943 dean of the College of Agriculture. In 1945 the Regents chose Fred to become the president of the University of Wisconsin, a position he held until 1958. In 1947 the departmental name was changed from Agricultural Bacteriology to Bacteriology. During this era, the department added notable faculty, including William Wright in 1914, Ira Baldwin in 1927, Elizabeth McCoy in 1930 and William Sarles in 1932. In 1943, Dr. McCoy became the second woman at the University, outside of the fields of home economics and nursing, to attain the rank of full professor. Dr. Baldwin had a long career of service to the university. In 1932, he became Assistant Dean of the College of Agriculture, in 1942 chair of the Department of Bacteriology, in 1944 Dean of the Graduate School, in 1945 Dean of the College of Agriculture, in 1948 Vice President of the University, in 1958 Special Assistant to the President of the University, and in 1966 Vice Present Emeritus and Professor Emeritus of the Department .
In 1955 a building dedicated to bacteriology research and instruction was built. This was later named E. B. Fred Hall to commemorate Fred's contributions to the department and the University. In 1958 E. L. Tatum became the first Bacteriology alumnus to win the Nobel Prize in medicine and physiology (with J. Lederberg and G. W. Beadle).
In 2004, E. B Fred Hall was demolished and the Microbial Sciences Building was built on the same site. In August 2007, the department moved into the new MSB. Also in 2007, four faculty from the former Food Microbiology and Toxicology Department join Bacteriology, greatly enhancing the Department's expertise in food microbiology. The department looks forward to many years of productive contributions to the university's mission and to the field of microbiology.