Simulating FLIR imagery requires integration of visual simulation technology with IR modeling and prediction. Analyses of simulated FLIR and consideration of training needs indicates that high fidelity simulation of all FLIR components is not required for many aircrew training applications. The different components of FLIR simulation i.e., predicting IR exitance from surface features, modeling atmospheric attenuation, and simulating sensor effects, are independent and an appropriate level of simulation complexity for each component must be selected for a particular application. Effective combinations of component fidelity for various training applications are described. Simulating sensor and atmospheric effects on FLIR imagery will have a high training payoff for many applications at relatively low cost. Developing a FLIR simulation system which will support thermally accurate IR predictions for any user specified mission scenario will require extensive development and data base support; the training applications which require such systems are limited.