Achillea pannonica Scheele is an octoploid species of the A. millefolium group. Based on herbarium and field studies, a taxonomic and phytogeographic account of this taxon is provided in the Central European part of its range. It is a clearly delimited species: no variation deserving taxonomic recognition was observed in Central European plants. Its range in the Czech Republic is divided into two parts including northern and central Bohemia, and southern and central Moravia, all warm to moderately warm and dry to moderately dry regions. Achillea pannonica is a heliophilous to heliosciophilous species of dry grasslands, fringe communities, thermophilous oak forests and some thermophilous (sub)ruderal communities. It grows on several types of rock and often prefers calcareous substrata such as limestone and loess. At several sites, it was observed to occur together with other yarrows. Hybridization with A. millefolium s. str. sometimes occur, and the new nothospecies, A. x incognita, is formally described.