The palaeointensity of the geomagnetic field has been derived from selected rock types of the Czechoslovakian West Carpathians using Thellier's and Van Zijl's methods. Igneous rocks of three geologic time periods were studied. The following values were determined for the ratio of the intensity of the geomagnetic field at the place and time of origin of the rock to the intensity of the laboratory magnetic field (parameter K): a) basaltic rocks (Upper Miocene to Quaternary) K=0.21-2.11; b) monchiquite (Lower Cretaceous) K=0.61; c) quartz porphyry (Middle Silurian) K=0.50.