The volatile compounds of 18 samples from the western Balearic Islands belonging to three taxa of theTeucrium marum L. complex (T. marum subsp. marum, T. marum subsp. occidentale and T. marum subsp. drosocalyx) were fractionated by distillation-extraction and analysed by means of GC-MS. Seventeen components were characterized and the quantitative data were subjected to multivariate and clustering techniques. Two main groups appeared, one comprising T. marum subsp. occidentale samples and the other grouping T. marum subsp.marum and T. marum subsp. drosocalyx accessions. Chemical data and taxonomic groupings generally agreed, but quantitative and qualitative differences within and between taxa were found. Specimens from Minorca and Cabrera islands showing intermediate morphological features between T. marum subsp. marum and T. marum subsp.occidentale were included within the T. marum subsp. marum-T. marum subsp. drosocalyx group in the Principal Component Analysis. The origin of these intermediate specimens is discussed, and it is suggested that they are local variants of T. marum subsp. marum which had an independent origin throughout its area.