The Hungarian Ministry of Agriculture established a chemical investigation service named. The Hungarian Royal Experimental Chemical Service of the City of Rijeka. According to the information found in the city's archive, as well as to the news published in the daily newspaper of that time "La Bilancia", the Service started its activity on April 8th, 1900. The Service was in fact the first organized institution of public health within this region and the current Institute of Public Health is its direct heir. At the end of the World War I, the city of Rijeka was incorporated to the Kingdom of Italy in 1924, while the territory of Susak came under the Kingdom of Yugoslavia. The Chemical Investigation Service, though changing different names, continued its activity. As the Provincial Laboratory for Hygiene and Prophylaxis, the institution carried on its activity from 1927 until the end of World War II in 1945. As the consequence of the frontier erected on the river banks of Rjecina, the Susak area remained without a single medical institution. The first organized institution of public health in this area was the Bacteriological Service in Kraljevica, established in 1923. The Health Care Center Susak was founded in February 1926 and moved in a new building located in Kumicića St. No 6. Subsequent to Italian occupation of Susak in 1941, the major parts of the Health Care Center moved to Crikvenica, continuing its activity within the district of Susak that came under the Independent State of Croatia (NDH). The smaller part of the Center that remained in Susak ceased its activity in 1942. After the liberation in May 1945, the Health Care Center came back to Susak. Due to the fact that the most of experts left the town by the end of war, the activity of the Laboratory in Rijeka was reduced in that period. In 1946 the organization structure had already been changed with Sanitary Epidemiological Service (SES) founded in Susak, and the Municipal SES established in Rijeka. Both institutions were on January 1st united into the regional Hygienic Institute in Rijeka. The Hygienic Institute and the Health Care Center Rijeka (founded in 1953) were unified into the Institute of Public Health on July 1st 1960. A huge improvement in preventive medical service was obtained by moving into a new building of the Institute in nowdays location in Kresimirova St. No 52a.