It was initially meant as the rural branch of the largely urban Yugoslav Democratic Party.
In the elections for the Yugoslav constitutional assembly of 1920, it gained 21% of the votes in Slovenia, thus becoming the second largest Slovenian party, after the Slovene People's Party, and it gained eight of the 38 Slovenian seats in the Yugoslav Parliament.
In the municipal elections of 1921, the Independent Agrarian Party maintained approximately the same percentage of votes, and managed to defeat the Slovene People's Party in several districts of southern Slovenia (Lower Carniola and White Carniola) and in the Celje region.
In the discussions on the Yugoslav constitution in 1921, the party adopted a rigidly centralist attitude.
As the majority of the Slovenian population at the time supported some sort of territorial autonomy for Slovenia, this decision proved very damaging for the party's future success.