This paper outlines crop improvement, strategic agronomy, and natural resource management research concerns central to CIMMYT¦s mission and which models can help address. Authors also discuss related issues, including model documentation and data management. Although CIMMYT has little comparative advantage in model development per se, the center has much to contribute to others' development and refinement efforts, to the availability of quality data, and to the promotion of models and training in their use, and active participation in these areas will ultimately result in better models for CIMMYT's own aims.