An HPLC-ESI/MS method that enables fast detection and identification of iridoid glycosides is described. Eleven iridoid glycosides known to occur in the genus Lamium-lamalbide, sesamoside, 6-beta-OH ipolamiide, shanzhiside methyl ester, dehydropenstemoside, barlerin (= 8-O-acetylshaiizhiside methyl ester), 6-O-syringyl-8-O-acetylshanzhiside methyl ester, lamerioside, lamiide, eriobioside, and ipolamiide, were identified by means of their retention time and ESI/MS data. This method was successfully applied to the identification of the iridoid composition of the n-butanol extracts of Lamium eriocephalum Bentham subsp. eriocephalum, L. garganicurn L. subsp. pulchrum R. Mill, L. garganicum L. subsp. laevigatum Arcangeli, and L. purpureum L. var. purpureum from the Turkish flora.