Chemical process simulators have undergone tremendous development in recent years. The new capabilities of these tools have changed the way chemical companies approach many aspects of process design and development, including thermophysical properties. What are the important thermophysical property needs in process simulation remaining to be addressed? What weaknesses in the application of thermophysical properties should users of process simulators be concerned about? Will chemical process simulators become the primary stewards of thermophysical property technology for the chemical industry? How can expertise in the thermophysical property area best be applied to optimize the impact on process design, development, and operation?