During archaeological excavations at Dzielnica (Opole province, southern Poland) in 2006 there were found obsidian flakes connected with the Stroked Pottery culture (Stichbandkeramik, SBK). Two pieces of well translucent obsidian with inventory numbers 45/06 and 56/06 have been analysed using neutron activation analysis in the Nuclear Physics Institute of the Czech Academy of Sciences, Husinec-Řež near Prague. Both samples were analysed for 8 major elements (Si, Ti, Al, Fe, Mg, Ca, Na, K), 18 trace elements (As, Ba, Co, Cr, Cs, Hf, Mn, Mo, Ni, Rb, Sb, Sr, Ta, Th, U, V, W, Zn and 13 elements from the group of rare earth elements. For determination of obsidian provenance we used various diagrams based on trace element ratios and comparison of the Polish artefacts with natural obsidian sources in Slovakia or in Hungary and also with Neolithic tools from Moravian Pained Ware I (Lengyel I) settlements Těšetice-Kyjovice and Brno-Žebětín. The Lengyel obsidian tools from Těšetice-Kyjovice form a homogenous collection and Williams-Thorpe et al. (1984) already studied them with conclusion on their provenance from the Slovakian source Carpathian 1. In our discriminating diagrams the Polish SBK obsidians from Dzielnica have the same position as the Lengyel samples from southern Moravia. We also confirmed the Th/U ratio (see Bigassi et al. 2000) as excellent marker to distinguish the Slovakian (Carpathian 1) and Hungarian sources (Carpathian 2). Th/U ratios of Dzielnica obsidians with values 1,75 and 1,78 (it is under 2) together with relatively lower contents of Ba, La, Th and usually also Na, Rb, Sc, Fe, Cs, Hf, Ce, Sm and Eu (see Williams-Thorpe et al 1984, Table 2) testify undoubtedly for the Slovakian source Carpathians 1. It seems the geochemical differences between the Slovakian source in the northern part of Zemplín Hills (Carpathians 1a, probably the principal source for prehistoric obsidian in Central Europe, see Přichystal & Škrdla 2014) and the well known source at Viničky in the southern part of Zemplín Hills (Carpathians 1b) are very inconspicuous. Macroscopic appearance of obsidians from Dzielnica is characteristic for the source Carpathians 1a. Using of obsidian from the Slovakian source at Paleolithic (from the Epigravettian onwards) and Mesolithic sites in Poland has been described by Hughes et al. (2018). References Bigassi, G., Biró, K. T. & Oddone, M. (2000): The Carpathian sources of raw material for obsidian tool-making. In: Dobosi, V. T., ed.: Bodrogkerestúr – Henye (NE Hungary). Upper Palaeolithic site, 221-240. Magyar Nemzeti Múzeum Budapest. Hughes, R. E., Werra, D. H. & Sulgostowska, Z. (2018): On the sources and uses of obsidian during the Paleolithic and Mesolithic in Poland. Quaternary International 468, 84-100. Přichystal, A. & Škrdla, P. (2014): Kde ležel hlavní zdroj obsidiánu v pravěku střední Evropy? / Where was situated the principal source of obsidian in prehistory of Central Europe? Slovenská archeológia LXII, 2, 215-226. Williams-Thorpe, O., Warren, S. E. & Nandris, J. G. (1984): The Distribution and Provenance of Archaeological Obsidian in Central and Eastern Europe. Journal od Archaeological Science 11, 183-212.