Fagus sylvatica L. and Fagus orientalis Lipsky are very close species, and an open question is if the two species are really separated. The main goal of this research was to clarify the presence of an unique F. sylvatica-orientalis complex or two distinct species by studying the sequence of the trnL-trnF region of chloroplast DNA (cpDNA). Twenty-nine F. sylvatica and twenty-two F. orientalis populations have been sampled, and to better delineate the systematic position in genus Fagus, Fagus taurica Popl., Fagus moesiaca Czecz., Fagus grandifolia Ehrh., Fagus crenata Bl., Fagus japonica Bl., and Fagus hayatae Palibin were also considered. The sequence analysis has permitted to resolve distinct groups corresponding to taxa such as F. sylvatica, F. moesiaca, F. taurica, and F. orientalis. Moreover, within the European beech, F. orientalis seems to be the ancestral species. This data is also corroborated by a higher variability found in F. orientalis than in F. sylvatica (9 and 6 haplotypes, respectively).