One task in the current work program of the Air Infiltration and Ventilation Centre is to identify and collate applicable default input data for ventilation and air infiltration modeling. (These data are also essential for coupled thermal and ventilation modeling.) Previous work has covered building airtightness data. The present task extends this to include data and algorithms concerning wind pressure coefficients, ventilation systems, occupancy, meteorological conditions, indoor pollutant modeling, and model evaluation data. The intention is to publish these electronically in the form of a "Ventilation Modeling Data Guide." It is intended that the ventilation modeling data guide should be largely based on results collected from various expert groups. This paper describes some potential data sources and gives an overview of the form of each data type. Additionally, it gives an illustrative application of the data. It is anticipated that the data guide may enable improved ventilation designs to be adopted.Units: Dual