The supercritical fluid extraction (SFE) of Greek sage leaves, i.e. Salvia fruticosa, was investigated at various operation conditions. Specifically, the effect of pressure, temperature and solvent flow rate on the extraction yield was examined. Thus, it was shown that as pressure increases, yield increases as well, while the effect of temperature depends on the extraction pressure. As for the flow rate, its increase mainly enhances the extraction rate. The SFE extracts were also compared with the essential oil obtained with hydrodistillation in terms of composition, revealing practically the absence of thujone and the presence of more biologically active compounds in SFE extracts. Finally, the experimental data were correlated successfully by a mass balance model based on Lack's plug flow model.