The Istrian Democratic Assembly (Croatian: Istarski demokratski sabor, Italian: Dieta democratica istriana or IDS-DDI) is a centre[4][5] to centre-left,[6] regionalist,[3][7] liberal[4] political party in Croatia primarily operating in Istria County.

IDS embraces principles of respect for human rights and freedoms, regionalism and historical characteristics of Istria, protection of private property and anti-fascism.

Party advocates decentralization of Croatia,[8] further development of the Adriatic Euroregion[8] and the establishment of a transnational and cross-border euro-region encompassing the whole of Istria.

The party was founded in 1990 by Ivan Pauletta, Elio Martinčić and Mario Sandrić, on the eve of the first multi-party elections in Croatia after communism.

One year later, IDS, dissatisfied with the way Ivica Račan and his coalition partners treated Istria, left the government, although they continued to support it in Parliament.

[9] This reduced the IDS from three to two representatives in the Croatian Sabor, and forced the party's parliamentary club to dissolve due to insufficient membership.