The rivers of Scandinavia and Finland are studied with regard to regime, regional distribution, and long-term variations in discharge. The regime studies are based on monthly mean coefficients, i.e. the relation between the monthly means and the average annual discharge for a 30-year period. Within the two main areas of nival highland and lowland regime and Atlantic snow and rain regime (Fig. 1), different regime types have been studied (Figs. 2 and 3, tables 2-4). The regional distribution has been estimated with correlation coefficients and relations between means for one year expressed as a percentage of the mean discharge of 1931-60. Some of the correlation coefficients are shown in Table 5. The variations of 30- and 10-year mean discharge in percentage of the mean discharge 1911-60. have been studied by the method of moving averages from the year 1901 (Figs. 4-9). As to the 30-year records there are four regions with different trends, the North Calotte with two parts, the Arctic Sea part and the inland, the Scandinavian high mountain district, Vestland in Norway, and the eastern lowland (Fig. 10). The relations between discharge, precipitation, and temperature are discussed. Based on the results of the studies, mainly those of regional distribution together with other elements such as the situation of drainage areas and runoff values, hydrological regions have been delineated, Fig. 11.