Seed oils from three commonly cultivated Echinacea species, Echinacea Angustifolia, Echinacea Pallida and Echinacea Purpurea, harvested in 1998 and 1999, were evaluated for physicochemical characteristics. Oil yield ranged from 13% to 23%, depending on Echinacea species and seed weight. UV/VIS and fluorescence spectra distinguished Echinacea seed oil by species. Vitamin E content of the oils ranged from 29 to 85 mg/100 g oil, with α-tocopherol constituting 83% of the total tocopherol. The oil was highly polyunsaturated and abundant in linoleic, oleic and palmitic acids, together comprising 95% of the total fatty acids. Echinacea seed exhibited three thermal transitions, two of which were reversing and descriptive of the species. Thermal oxidation, by differential scanning calorimetry (DSC), segregated Echinacea seed oil by species, based on oxidation temperature. Echinacea seed oil was separated, by TLC, into fractions corresponding to alkamides, ketoalkenes, echinicoside and chicoric acid, depending on species.