D/H studies of fluid inclusions of speleothems of the Soreq cave (Israel) are made using the method of vacuum thermal extraction. D/H measurements of present-day carbonate pool margins and waters show that the value of the vacuum thermal extraction fractionation Δ e x (=δD e x t r a c t e d w a t e r -δD c a v e w a t e r ) is -30.0+/-1.4%% for the Soreq cave deposits. D/H analyses of fluid inclusions of two fossil speleothems formed during periods equivalent to glacial times suggest that their isotopic compositions follow the global Meteoric Water Line (MWL) δD-δ 1 8 O relationship, compared to present-day waters which follow the Mediterranean Meteoric Water Line (MMWL) trend. Two samples from interglacial periods show isotopic trends between these lines. These differences are presumed to reflect cooler less evaporative conditions in the Eastern Mediterranean Sea during glacial times.