The doctoral dissertation deals with the analysis of metal threads in historical Croatian textiles, liturgical vestments and folk costumes from the 17th to the 20th century. The area of the whole of Croatia is covered, all regions in which metal threads appear on historical textiles, in a way and to the extent that has not been researched so far. The independent narrow stripes and wires, and the srma that was formed by a combination of metal thread wrapped around non-metal textile yarn were collected and analysed. Using physicochemical methods SEM-EDX (scanning electron microscopy with energy-dispersive X-ray detector), XRF (X-ray Fluorescence) and PIXE (Particle Induced X-ray Emission), the analysis of the composition and content of metals in the threads was performed. By comparing the methods, it was determined that the SEM-EDX is the most suitable for the analysis of historical textiles if cross-sectional analysis is also performed, because it is fast, simple and non-destructive. By cross-sectional analysis of metal threads with the SEM-EDX method, it was determined whether the metal threads were homogeneous or gilded, or silver-plated. The composition and structure of non-metal textile yarn were determined by light microscopy. Metal threads were primarily made of gold, silver or copper and their alloys, but lately less valuable metals having a similar shine have generally been used. Non-metal textile threads in srma are most often made of silk, cotton and linen. The aim was to determine which types and composition of metal threads were used in different regions of Croatia, which can serve as a database for the restoration and conservation of valuable historical textiles. Also, according to the composition of metal threads, the technology of production threads can be determined and the temporal and spatial dating of textile objects can be determined approximately.