This overview paper provides a foundation for the discussion of methods and techniques to integrate spatial ecological models with the technology of geographic information systems (GISs). A brief review is provided of historical modeling approaches for terrestrial, freshwater, and marine ecosystems that have some spatial component or can be extended into space. Examples of current spatial models are discussed for these ecosystems, and the use of distributional mosaic models for the simulation of broad-scale landscape disturbances such as fire and pests is examined. Spatial modeling is terrestrial and freshwater ecosystems in more advanced than in marine systems; however, marine systems are well suited for the application of GIS's and spatial models. Future needs and directions that will enable ecological models to capitalize on the capabilities of GISs are discussed with regard to data base management; remotely sensed data; landscape-level models; model-based management systems; data and model sensitivity, errors, and uncertainties; and environmental risk assessment.