A membrane inlet mass spectrometric (MIMS) method is presented and compared with a static headspace gas chromatographic method (HSGC) for the determination of terpenes in water. The MIMS method provides a very simple and fast analysis of terpenes in water, detection limits being relatively low, from 0.2 μg l−1 for monoterpenes to 2 μg l−1 for geraniol. The analysis of terpenes by the HSGC (equipped with flame ionization detector, FID) method is more time-consuming and the detection limits (2 μg l−1 for monoterpenes to 100 μg l−1 for geraniol) are higher than with MIMS. However, the HSGC method has the advantage of determining individual mono- and sesquiterpene compounds, whereas MIMS provides only separation of different classes of terpenes. Both methods were applied to the analysis of mono- and sesquiterpenes in several condensation water samples of pulp and paper mills.