Cherry seed oil, from the Rosaceae family, prunoid subfamily, is characterized by the existence of about 10% alpha-eleostearic acid. The structure of the acid was proven by H and C-13 nuclear magnetic resonance. The triacylglycerols of this oil were identified and quantitated by high-performance liquid chromatography by means of several types of detectors. alpha-Eleostearic acid was not found in the seeds of previously studied prunoids (almond, peach, apricot and plum). The main fatty acids found in the seeds of cherry and other prunoids were linoleic (L), oleic (O) and palmitic acids, and the major triacylglycerols were LLO, LOO and OOO. These chemical data support the botanical relationship within the prunoid subfamily and show the proximity of cherry to the Chrysobalanaceae family.