This study investigated the different forms and availability of P in soil profiles from temperate forests in southern Chile (two sites: Nothofagus obliqua (Mirb.) Bl. and Nothofagus betuloides (Mirb.) Oerst.) and Flanders, Belgium (two sites: Pinus nigra Arnold and Betula pendula Roth). Soils were sampled according to genetic horizonation and analysed for organic matter, oxalate-extractable P, Al and Fe, total inorganic P and total organic P. Phosphorus availability was assessed using an isotopic exchange technique and anion exchange membranes. The total P content was higher for the Chilean andosols and remained relatively high in the whole soil profile (1413-187 mg P kg-1) whereas total P decreased sharply in the lower horizons of the Flemish podzols (575-4 mg P kg-1). There was a strong predominance of organic P in the Chilean soils (up to 90% of total P). The high volcanic activity in Chile is responsible for the large amounts of allophone, which entail high P-fixing capacities in these soils. Notwithstanding the much larger total P content in Chilean andosols compared to the Flemish podzols, both soil types feature comparable amounts of available P (AEM-P). The two phosphorus availability indices (IEP and AEM-P) correlated rather well for the Flemish forest sites (R² = 0.67), while the same correlation was lacking for the Chilean soil profiles (R² = 0.11). However, a strong relation between AEM-P and the organic matter content of the andosols emerged. The presence of Al and DOC in the AEM-extracts of eight selected Chilean soil samples suggests the extraction of organo-mineral colloids by the membrane. The lack of correlation between AEM-P and IEP for the Chilean soils may be related to the presence of these colloids, as they may lead to an overestimation of IEP as well as biased AEM-P values. Differences in forms and availability of phosphorus between the Chilean and the Flemish soil profiles were mostly ascribed to differences in soil properties rather than to differences in anthropogenic influences Este ...