Keywords:Spatially explicit fate models GIS Data assimilation Analytical solutions Simplifl catión A review by Hollander et al. (in preparation), discusses the relative potentials, advantages and shortcomings of spatial and non spatial models of chemical fate, highlighting that spatially explicit models may be needed for specific purposes. The present paper revie ws the state of the art in spatially explicit chemical fate and transport modeling in Europe. We summarize the three main approaches currently adopted in spatially explicit modeling, namely (1) múltiple box models, (2) numerical solutions of simultaneous advection-dispersion equations (ADE) in air, soil and water, and (3) the development of meta-models. As all three approaches experience lfmitations, we describe in further detail geographic information system (GlS)-based modeling as an alternative approach allowing a simple, yet spatially explicit description of chemical fate. We review the input data needed, and the options available for their retrieval at the European scale. We also discuss the fmportance of, and lfmitations in model evaluation. We observe that the high uncertainty in chemical emissions and physico-chemical behavior in the environment make realistic simulations difficult to obtain. Therefore we envisage a shift in model use from process simulation to hypothesis testing, in which explaining the discrepancies between observed and computed chemical concentrations in the environment takes fmportance over prediction per se. This shift may take advantage of using simple models in GIS with residual uses of complex models for detailed studies. It also calis for tighter joint interpretation of models and spatially disfributed monitoring datase ts, and more refined spatial representation of environmental drivers such as landscape and climate variables, and better emission estimates. In summary, we conclude that the problem is not "how to compute" (i.e. emphasis on numerical methods, spatial/temporal discretization, quantitative uncertainty and sensitivity analysis...) but "what to compute" (i.e. emphasis on spatial disfribution of emissions, and the depiction of appropriate spatial patterns of environmental drivers).