The hydrodistilled essential oils of 16 cultivars of Mentha, viz. M. arvensis L., M. spicata L. and M. citrata Ehrh., were analysed and compared by gas chromatography and gas chromatography-mass spectrometry. Fifty-seven constituents representing 92.8-99.8% of the total essential oil composition were identified. Monoterpenoids (88.1-98.6%) are the major constituents of the essential oils. The major constituents of the oils in 9 cultivars of M. arvensis are menthol (73.7-85.8%), menthone (1.5-11.0%), menthyl acetate (0.5-5.3%), isomenthone (2.1-3.9%), limonene (1.2-3.3%) and neomenthol (1.9-2.5%). Carvone (51.3-65.1%), limonene (15.1-25.2%), -pinene (1.3-3.2%) and 1,8-cineole (≤0.1-3.6%) are the major constituents in 5 cultivars of M. spicata, while in one cultivar (Ganga) of M. spicata the major constituents are piperitenone oxide (76.7%), α-terpineol (4.9%) and limonene (4.7%). Linalool (59.7%), linalyl acetate (18.4%), nerol (2.0%), trans-p-menth-1-en-2-ol (1.8%), a-terpineol (1.5%) and limonene (1.1%) are the major constituents of M. citrata.