The Polish science of the constitutional law is extensively interested in the problem of the purpose of the exitence of the upper house of the parliament in unitary countries. The issue is especially interesting in Poland, where different political parties, in their programs, propose to abolish the Upper House of the Parliament, the Senate. The functioning of the upper chamber of the parliament in the Republic of Croatia seems to be extraordinarily interesting as far as this issue is concerned. Croatia adopted its first constitution on 22 December 1990. According to its first version the House of Parliament was to have two chambers. It consisted of the House of Representatives and the House of Zupanii (the House of Counties). On 28 March 2001 the constitution was mended, as a result the House of Counties was abolished. The article presents the analysis of the reasons for which the House of the Zupanii was created, its structure, references, the functioning and the reasons why it was abolished. The parliamentary traditions in Croatia date back to 13 th century, but in the past Sabor (the Parliament) was never bicameral. The decision to appoint the House of Zupanii, although an important part of the political system, were made in at least curious circumstances. Franjo Tudjman’s opinion had the biggest influence on the creation of the House of Zupanii, it was made, although main experts from the constitutional commission opposed, as they thought it’s against the Croatian tradition. While designing the references and the position of the House in the system, the commission took for example the solutions used in Italy and Spain. The House of Zupanii was supposed to represent the regional interests, which was stressed by the elective system to this chamber. The item literature pointed out that Croatia is considerably different to the countries from which it took the example. The House of Zupanii had limited references, which were mainly to serve as a deliberative body for the lower house of the parliament. It also had a suspensory veto, for the bills passed by the House of Representatives, which it really didn’t use. The decision to abolish the House of Zupanii was made following certain political interest. Despite that it seems that nine years after the liquidation there is no intention to bring the upper house of the parliament in Croatia back to life. We come to a conclusion that the science of the constitutional law and the Croatian political scientists considered the experiment with the upper house of the parliament as a failed one.