EN
Our study provides a comprehensive answer to the question of how the main nationalities and denominations in Slovakia voted in the third parliamentary elections in the Czechoslovak Republic. Using municipality level aggregate data, we apply two modern methods of ecological inference to provide an answer. Their reliability is tested using known nationality and denomination distributions from the 1930 Census that followed 13 months after the elections. Our results are based on the method proposed by Greiner and Quinn and evaluated in a confrontation with previous works on the electoral support for parties in the Czechoslovak Republic as well as analyses of politically, nationally and religiously homogeneous environments where ecological fallacy can be avoided. Our findings support the assertions about the importance of national and religious division lines in party support in the late 1920s Slovakia.