The geochronological understanding of the Precambrian crystalline shield of North-West Greenland (75–79°N) is at a rudimentary stage. Isotopic data from three major rock complexes—the Etah meta-igneous complex, the Kap York meta-igneous complex, and the Kivioq Havn gneiss and supracrustal complex—all show scatter indicating disturbed Rb–Sr isotope systems. This may reflect widespread reactivation of the crust in Proterozoic (Hudsonian) time. However, the majority of the samples define errorchrons that are regarded as geologically significant, and although the ages are poorly constrained, the data demonstrate the presence of both Archean and Proterozoic terranes.The Etah complex is Proterozoic in age (errorchron age ca. 1850 Ma), whereas the Kap York and Kivioq Havn complexes represent late Archean material (errorchron age ca. 2700 Ma). These ages compare favourably with isotopic age information from adjacent Canada in southeast Ellesmere Island and Devon Island, where correlatable Archean and Proterozoic rock complexes occur.