The soil cation-exchange capacity (CEC) has edaphological, pedological and environmental importance. CEC pedotransfer functions were developed for Danish soils by multiple linear regression analysis of 1643 samples from a nation-wide 7 km grid survey. By partitioning the data into four groups podzolic B-horizons, organic soils (>10% soil organic matter), calcareous soils (>0.1% CaCO 3 ), and a 'normal data set', four separate functions were developed. Without further partitioning of the normal data, 90% of the variability in CEC values can be modelled by using clay and organic matter content as independent variables. This yields a standard error of the estimate of 1.99. The average soil organic matter-CEC is 284-291 cmol c kg