The analysis of Pelargonium graveolens essential oil is reported using comprehensive two-dimensional gas chromatography with quadrupole mass spectrometric detection (GCXGC-qMS). A spectral acquisition rate of 20 Hz was achieved by using a reduced mass scan range of 188 u. 65 components were identified within the two-dimensional separation space based upon retention index and mass spectral matching with literature data. Very high quality mass spectra were obtained, which facilitated accurate library matching, without the need for background correction. High efficiency in the short, fast-GC second dimension column was achieved by applying the principles of vacuum-GC. It is demonstrated that facile determination of the key citronellol : geraniol ratio and the amount of 10-epi-γ-eudesmol in geranium essential oils using GCXGC will be possible. The method should be generally suited to the analysis of similar essential oil samples.