abstract the phylogenetic relationships of the three abiesspecies grown in balkan peninsula were investigated through their volatile secondary metabolites. the leaf oil of a statistically representative sample of sympatric abies alba, a. cephalonica and a. borisii-regis trees was obtained and analyzed by means of gc and gc/ms. forty components were identified and quantified on the basis of their retention indices, their mass spectra characteristics and relative peak areas. the majority of the investigated oils were found to consist of monoterpenes. the major constituents were the same in all studied species but their content varied significantly, thus allowing the assignment of characteristic chemical profiles based on their contribution rank. the variation of the oil constituents and their possible taxonomic significance is discussed.