A new multizone airflow and contaminant dispersal program CONTAM93 is described. While this program is based on existing theory of network airflow analysis and contaminant dispersal, it employs a unique graphic interface for data input and display. The interface uses a sketchpad to describe the connections between zones and icons to represent zones, openings, ventilation system components, and contaminant sources and sinks. The program, its graphic interface and plans for its further development are described.