The museum of the Poreč territory is the heir of two previously established museums: the Regional Archeological museum of Istria, founded in 1884 and the City Museum for Arts and History, founded in 1926. The collections of both museums are incorporated in today's museum, located from 1952 in the baroque palace of the Sinčić family. The Museum take care of several buildings as well as other cultural and historical areas in Poreč and its surroundings. The Regional Archaeological Museum of Istria was the first museum institution in Istria. It was founded in 1884. Its collections have been formed through donations and archaeological excavations in Poreč and broader Istrian areas. The main part of the collection have been moved in the early twenties of the 20th century from Poreč to Pula, in today's Archaeology Museum of Istria while the remaining part has been incorporated in the City Museum of Arts and History, founded in 1926. The archeology collection still held a major position of interest in the Museum of Poreč but a growing importance has been given to collecting objects of historical and cultural value too.

After World War II, the Museum opened its doors again in 1952 under the name Kotarski muzej Poreč (District museum Poreč) and later Zavičajni muzej Poreštine (Museum of the Poreč territory). From that moment the activities of the museum are bonded to the area of Poreč and its surroundings: building and expanding the collections with archaeological, cultural - historical, historical, ethnographic and artistic museum objects.