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[Abstract] LISEM model (Limburg Soil Erosion Model) is actually being developped in order to perform dynamic simulations of surface runoff and erosion in catchments. This model is also proposed as analysis support system for soil erosion problems derived from agricultural management practices, which can be used as a kernel of an expert system for agricultural and environmental planning. Hydrological response of LISEM 5.0 is analysed on the basis of soil water flow parameter values of the Green-Ampt sub-model, which estimates infiltration rates. Observed hydrographs in the stream gauge installed in a catchment were tested with those simulated by LISEM 5.0. Observed hydrographs shows that the hydrological response of experimental catchment corresponds to a variable source type. By contrast, given the assumptions of LISEM 5.0 for calculating runoff , the calculated hydrological response is always hortonian.Results showed that, for any set of infiltration parameters, Green-Ampt infiltration submodel is not able to simulate the observed streamflow discharge (variable source). This occurs because the rainfall intensity-infiltration ratii do not allow a generalized hortonian surface runoff as predicted by LISEM 5.0. Hortonian runoff only may be possible at short times and limited to small areas, and does not appear to be significant in the observed hydrographs.