The variability of the essential oils produced by Achillea collina (A. millefolium agg., Asteraceae) has been studied. Plants were collected at five different sites in the urban area of Vienna, Austria, and separated into inflorescences, leaves and stems. A remarkable variability could be observed. Chamazulene was present in all samples and was the main oil compound in inflorescences and the lowest in stems. p-Pinene, sabinene, and 1,8-cineole were the most important monoterpenes and (3-caryophyllene, germacrene D and caryophyllene oxide prevailed amongst the sesquiterpenes. Stems being low in volatiles showed high proportions of linoleic and palmitic acid in their oils. In comparison to other taxa of the A. millefolium group the present A. collina plants contained only very low proportions of bomeol and camphor in their oils.