The Nordkalott project area comprising Norway, Sweden and Finland north of the Polar Circle is underlain by the Baltic shield and the Caledonides. Geochemical mapping of the 250 000 km 2 area involved 8 types of sample collected at a density of 1 sample station per 30 km 2 . Three of the 8 types are of particular interest for IGCP 259 because of their common use in regional geochemical surveys: (1) Fine fraction of inorganic stream sediment, (2) stream organic matter (peat), and (3) fine fraction of till. Comparisons of abundances and spatial distributions of elements in the different media show that element abundances are different in the two types of stream sediment but the element distribution patterns are mostly similar. By contrast, more than half of the 15 elements considered show different distribution patterns in till and stream sediment. The differences reflect the extent to which stream sediments have undergone chemical changes in the surficial environment. The comparisons also show that the lithologically/mineralogically and physiographically different regions, the Caledonian fold belt and the Baltic shield, are differently affected by the surficial processes. In the Baltic shield the elements Co, Cr, Mg, Na, Ni, and Sc appear correlatable with the use of simple regression techniques whereas Cu, Fe, Mn, and Zn can possibly be made correlatable if the enhancing effect of organic matter and secondary precipitation of Fe and Mn oxides can be estimated or modelled. For the remaining elements in the present study, Ba, La, Ti and V, an explanation of the different behaviour in till and stream sediment (and from different analytical methods) is needed before possibilities for correlation can be judged. The Nordkalott project has provided comprehensive data sets which can be used to study how results from till geochemical mapping may be correlated with results from stream sediment mapping on a regional scale. This is relevant to international geochemical mapping over the glaciated northern hemisphere where changes in physiographic conditions make the use of different media necessary.