The aim of study was to determine the variability of 20 yarrow populations introduced into ex situ conditions, in respect of selected developmental traits as well as content and composition of biologically active compounds (essential oil, tannins, flavonoids and phenolic acids). Field experiment was established at the Experimental Station, Department of Vegetable and Medicinal Plants. Morphological observations and harvest of raw material were carried out in the second year of plant vegetation, at the beginning of blooming. Investigated populations differed significantly in respect of developmental features as well as content and composition of identified compounds. The highest differences among the populations concerned fresh mass of herb (0.46–1.79 kg per plant), number of shoots per m2 (64–243) and length of the longest internode (42–158 mm). Total content of essential oil ranged from 0.10 to 1.00%. Among 24 identified compounds β-pinene, 1,8-cineole, terpinene-4-ol, nerolidol and chamazulene were the dominants. According to content of these compounds, three chemotypes were distinguished within investigated populations, i.e.: β-pinene, β-pinene + chamazulene and 1,8-cineole type. Content of tannins ranged from 0.38 to 0.90%. Four flavonoids were identified and apigenin 7-glucoside was present in the highest amount (from 9.87 to 475.21 mg × 100 g−1), while the highest differences between populations concerned the content of luteolin-3',7-diglucoside. Within phenolic acids, three compounds (caffeic acid derivatives) were identified. Rosmarinic acid was the dominant one (75.64–660.54 mg × 100 g−1), while cichoric acid differentiated investigated populations the most.