This year Zemun Hospital--Clinical Hospital Center Zemun celebrates 230th anniversary of continuous work, thus becoming the oldest medical facility in Serbia.The exact date of the hospital founding has been often questioned in history. Various dates appeared in the literature, but the most frequent one was 25th of February 1784. Until now, the document which confirms this has never been published. This article represents the first official publication of the document which confirms that Zemun Hospital was indeed founded on this date. The first hospitals started emerging in Zemun when the town became a part of the Habsburg Monarchy. The first sanitary facility ever formed was the"Kontumac"--a quarantine established in 1730. Soon after, two more confessional hospitals were opened.The Serbian (Orthodox) Hospital was founded before 1769, whereas the German (Catholic) Hospital started working in 1758. Both hospitals were financed, amongst others, by the Town Hall--the Magistrate. In order to improve efficiency of these hospitals, a decision was made to merge them into a single City Hospital. It was founded on 25th February 1784, when the General Command ordered the Magistrate of Zemun to merge the financess of all existing hospitals and initiate the construction of a new building. Although financially united, the hospitals continued working in separate buildings over a certain period of time.The final, physical merging of these hospitals was completed in 1795.