Business Process Simulation (BPS) has been widely accepted as a modus operandi for evaluating business applications and for understanding the strength and weakness of the implemented system. However, less attention has been devoted to applying BPS for simulating traffic intensive applications hosted on the Internet. These systems are inherently different from typical enterprise-wide business applications since the number of hits received at the application's Web site can fluctuate to a large degree depending on the external factors (e.g. political unrest causing overbooking in airlines). In addition, every hit does not necessarily lead to a successful completion of a transaction since users can navigate away to other Web sites during the browsing. This paper describes our ongoing research on developing a modeling support environment for simulating traffic intensive Web applications. The proposed system utilizes transaction logs and Web server logs which contain vital information about the interaction between clients and the Web application. As the project is still in its early phases, the paper mainly studies the modeling requirements, discusses the difficulties have to overcome, and concludes with our future work. © 2008 IEEE.