The wax ester fraction of various plant oils was isolated by normal-phase HPLC (NPLC) on-line coupled to GC via the on-column interface and applying concurrent eluent evaporation. The esters were analyzed by on-line NPLC-GC-MS and by comprehensive two-dimensional GC with flame ionization detection (GC6GC-FID) off-line combined with NPLC-GC. GC6GC-FID enables to group the various classes of wax esters, in particular the phytol esters, geranylgeraniol esters and the straight-chain esters of palmitic acids and the unsaturated C 18 acids. Optimization of the GC6GC columns and the conditions must take into account the limited thermostability of the diterpene esters. Chromatograms are shown for a range of oils, with particular focus on the various classes of wax esters in olive oil and the geranylgeraniol esters 22:0 and 24:0 in a variety of oils.