The Congress of Internists was launched in the Kurhaus on 20.04.1882. It brought together 188 of the best-known doctors from German-speaking countries, including Emil Pfeiffer, Robert Koch (Berlin), Wilhelm Ebstein (Göttingen) and Adolf Kussmaul (Strasbourg). The latter, together with Professors Carl Gerhardt (Würzburg), Ernst von Leyden (Berlin) and Eugen Seitz (Giessen), had issued invitations to this constituent meeting of the "Congress for Internal Medicine" in order to "[...] promote the scientific and practical interests of internal medicine through personal contact." The first congress president, Friedrich Theodor von Frerichs (Berlin), presented the medical advances of the time. Three companies exhibited their medical devices, microscopes and medicines. The highlight of the Congress of Internists was Robert Koch's lecture on his discovery of tubercle bacilli. From the very beginning, the Congress of Internists made Wiesbaden a hub for medical and scientific exchange in the German-speaking world. With a few exceptions, he remained loyal to the city during the early years.

During the First World War, the internist congresses were canceled. During the first congress of internists after the war in 1920, the previous name was abandoned and the organizing society was renamed the German Society of Internal Medicine (DGIM). In 1921, the 33rd Congress of Internists already featured 100 lectures. After an interruption during the Second World War, the 54th Congress of Internists initially met in Karlsruhe in 1948, after which all but one of the events were held in Wiesbaden again. In the second half of the 1950s, internists were faced with health policy problems; in particular, internal medicine was no longer specifically listed in the new medical fee schedule. As the DGIM could not deal with political issues according to its statutes, the Professional Association of German Internists was founded in 1959. Every spring, several thousand doctors meet at the Congress of Internists with its numerous scientific lectures and training events.

The dates of the 113th Congress of Internists and its 125th anniversary in 2007 show the development it has undergone: Around 8,500 participants attended around 290 lectures and discussion events, 135 companies presented their medical products. In 2007, the Congress of Internists was also open to the lay public for the first time: in the town hall and on the town hall forecourt, anyone could find out about various clinical pictures and ask DGIM experts questions during the congress weekend. Compared to the first congress of internists, the specialist topics also showed the paradigm shift in medicine: "The elderly patient" has only become an important focus thanks to the successes of medicine. Following the demolition of the Rhine-Main Halls, the 2015-16 Congress of Internists was held in Mannheim. It is set to return to the new building in 2018.