Pazin was first mentioned as Castrum Pisinium in a 983 deed regarding a donation by Emperor Otto II to the Diocese of Poreč. It then belonged to the Imperial March of Istria, which had originally been under the suzerainty of the newly established Duchy of Carinthia in 976, but separated together with the March of Carniola in 1040.
The Istrian contract (Razvod istarski) was written in 1325 in the Croatian language and in the Glagolitic script.
Until 1918, the town (under the name Pisino) was part of the Austrian monarchy (Austrian side after the compromise of 1867), seat of the district of the same name, one of the 11 Bezirkshauptmannschaften in the Austrian Littoral province.
In the same year, Pazin and all the Peninsula of Istria were transferred to the Kingdom of Italy. Benito Mussolini, then, introduced a fascist regime in Italy which, under the “Duce”, tried to Italianize all of the region. However, most of Istria became part of Yugoslavia after World War II.