This dissertation deals with the architecture of convents and convent churches in the Franciscan Province OFM Bosna Srebrena (Bosna Argentina lat.) embracing thus 19 existing sites in Bosnia and Herzegovina, Serbia, Croatia, and Kosovo (UN Res 1244). The sites are located within five dioceses: Archdiocese of Vrhbosna, Archdiocese of Belgrade, Archdiocese of Zagreb, Archdiocese of Pristina, and the Diocese of Banja Luka, and have been erected from the mid-XIX century until the present time. The topic The Franciscan architecture in OFM Bosna Argentina in XIX and XX century is first introduced with records of the general facts of Bosnian history, about the Franciscans in general, and particularly the Franciscans in Bosnia. Before the intricate analysis of the architecture in the Province, the work focuses on fundamental discussion about the monasticism of mendicant orders and the Franciscan architecture. Furthermore, some insights are given about the European and Bosnian surrounding context of Franciscan and overall Catholic architecture, along with the overview of local sacred architecture. The main scope of the work is the selection and portray of the most representative and illustrative convent sites in the Province, from which six particular study cases were found highly relevant. The selection was made cautiously in order to properly represent the colourful variety of architecture in the Province. Besides the target era and area, the dissertation deals with all known previously demolished layers of the Medieval architecture, as well as with some other interesting influencing sites in the Province, which set the ground for the addressed buildings. The findings include a number of never before published materials and archive documents, built and rejected projects, facts and figures, as well as data about the involved architects, sculptors, painters, and artistic workshops.The foremost idea of the work is detailed research and presentation of the architectural values and highlights in the Province, originally contributing to this field of history of Bosnian architecture, which is not comprehensively researched until today. Established hypotheses examine not only some of the most important questions of the sole architecture, but also discuss the crucial architectural settings of the convents and convent churches belonging to OFM Bosna Argentina, within the surrounding spatial and historical context. Besides being conscious of the numerous other side-influencing ideas, that were excluded from the research, the work concentrates on the architecture only, underlining the seclusion from possible misinterpretations of politics, nationalistic and religious relationships, due to often clashing situation between different religions, nationalities, and minorities in Bosnia. The methods of research include established models of examining the history of architecture: mostly the fieldwork, archive and library research, comparative analysis, interviews with involved figures, and the systematic evaluation of retrieved data.