During the thirty years of its existence, the extensive archives of the “Gaj” Tamburitza Cultural Society in Zagreb have managed to preserve older collected works and magazines, books, scores of vocal music with instrumental accompaniment and instrumental scores composed for tamburitza orchestras. This work purports to display musical supplies and inventory of the Society, as well as place the Society’s activity within the context of cultural clubs, starting with the introduction, which will cover the history and development of tamburitza in general, and in Croatia. According to the list of instrumental tamburitza scores, formatted in an excel table, the orchestra counts 740 music scores. Besides this list, the work intends to outline the history and organisation of the Society, as well as its repertoire and the special occasions, performances and competitions in which the Society took part. The goals and aims of this work are to get new insights into the Society’s activity and repertoire through the list of musical scores, the overview and the analysis of the archival and other sources. An extensive list of bibliography dealing with tamburitza, as well as administrative documentation, together with bibliography on historical musicology and ethnomusicology works covering tamburitza and archive administration, as well as other branches of historical musicology and ethnomusicology, have been the foundation in the investigation of the cultural club’s activity and the management of its holdings. Besides cataloguing, reading and investigating the documents, this work has also made use of the interview method with Krešimir Raĉić, orchestra’s conductor, in order to portray orchestra’s organisation and activity. This work is accompanied by a table list of inventory, an analytical table, images and similar sources that seemed to be important during the elaboration of the theme.