The chemical compositions of parsley seeds essential oils from 11 cultivars (three of leaf parsley and eight of root parsley) obtained from different commercial sources, marketed in Poland, were compared. The constituents of essential oils were investigated by GC, GC-MS and 1 H-NMR spectroscopy. Eighteen components (representing approximately 99.9% of the total oil composition) were identified in the cultivar 'festival'. There were significant differences between quantities of the oil components. The content of phenylpropene derivatives in the seed essential oils permits convar. crispum (leaf parsley), main constituent myristicin, and convar. radicosum (root parsley), main constituent apiole, to be distinguished.