The article presents the results of a systematic search for fragments of medieval music manuscripts in Slovenian libraries. The material found is analysed in respect of contents (types of manuscripts), notation, and date of the origin. Conjectures are made about the time of the destruction of the manuscripts to which the fragments belonged, as well as concerning the question of which fragments belonged to manuscripts that were actually in use in the country and which have just casually arrived in their present locations. Some more interesting fragments are described in detail