The author presents a comparative legal analysis of the segments of construction law in Croatian and Slovenian law, with the aim of pointing out the differences that exist between them. Considering that this is a relatively new legal institute, which was somewhat earlier standardized in Slovenian law in relation to Croatian law, in the introductory exposition, a brief review was made of the occurrence of the construction law and the reasons for earlier non-regulation. The second part of the paper is dedicated to the stipulations of Act on ownership and Property Code of the Republic of Slovenia. This part refers to the conceptual definition of the construction law, in order to classify it in a certain broader unit, to which it belongs - genus proximum - searching for the closest relative, emphasizing the important characteristics that make it specific in relation to other property rights. In the third part of the paper, the author analyses the stipulations related to the subject of building rights, with reference to the dilemmas that exist in that sense, both in Croatian and Slovenian jurisprudence, as well as in the legal science of some other countries. The fourth part of the paper is dedicated to the stipulations that regulate the acquisition and duration of construction rights. Considering that derivative acquisition, among other things, characterizes the existence of bases and ways of acquisition, first possible bases of acquisition are presented, and then entry in appropriate public books as a way of acquiring this right and its duration. The concluding part of the paper summarizes the results of the analysis and evaluates the considered legal solutions, with the presentation of reasoned objections to the existing regulations, all with the aim of eventual amendment of the right to build in the legal systems in question.