Variscan metamorphic complexes of the Apuseni Mountains in Romania continue westward in the pre-Neogene basement of the Pannonian Basin. To better understand the spatial relationship between the two neighbouring areas and to have a chance to sketch their common metamorphic evolution, geochemical and petrologic features of specific rock types must be focused on. The most promising lithologies for this reason are diverse metabasic rocks, first of all, amphibolites. Previous work on determination of the protolith of metabasic rocks from the Körös Complex, a large subarea of the eastern end of the Tisza microplate in Hungary, gave contradictory results. To solve this problem, major and trace element data of 60 amphibolite samples were treated by traditional geochemical methods as well as by a multivariate geo-mathematical approach. For the mathematical study a combination of correlation, principal component, cluster and discriminant function analyses were used in order to recognize presence of different igneous series in the area. The results of the geo-mathematical treatment were also tested and confirmed by the evaluation of trace element and REE data of representative unaltered samples. Based on this examination three geochemically distinct groups of amphibolites can be defined. Each of them can be related to structural units of different metamorphic evolution. The lowermost tectonic realm is dominated by orthogneiss containing metabasic xenoliths of MORB character. This unit is covered by a sillimanite-biotite paragneiss zone in which garnetiferous amphibolite intercalations occur exhibiting highly differentiated OIB basalt protolith. The topmost unit consists essentially of amphibolites and biotite gneisses representing a pre-metamorphic volcanoclastic series. Here, the amphibolite members are of T-MORB character tholeiites that possibly developed in a back-arc basin.