Rb-Sr whole rock isochron dating of Svecokarelian prekinematic granitoids from a single outcrop ca. 20 km NNE of Ludvika, south central Sweden, gives an age of 1799 ± 10 Ma. Zircons separated from one of the granitoid samples yield a U-Pb discordia age of 1869+9-8Ma. Regional sampling of similar granitoids in the Ludvika area results merely in a Rb-Sr whole rock errorchron of 1770 ± 10 Ma, thus emphasizing the importance of restricting sampling in older metamorphic terrains to a small area with good geological control. Rb-Sr whole rock dating of Svecokarelian metarhyolites (leptites) from the Yxsjöberg area, WSW of Ludvika, fails to give a meaningful age.