Process calculi are mathematical tools used for modeling and analyzing the structure and behavior of reactive systems. One such calculus, called APi-calculus (an extension to Pi-calculus), provides support for modeling migration, intelligence, natural grouping and security in agent-based systems [18]. In this article, a visualization tool for the APi-calculus is proposed. Although an invaluable formal method for mobile agent systems, APi-calculus (as other calculi) is quite complex and not well suited to practical applications by itself. Due to the dynamic nature of mobile agents, a graphical program based on the mathematics of the calculus would enhance the use of the calculus and its attraction to the mobile agents industry. The ability to provide instant demonstration of a designed system to the user and the support for verification and validation of such systems specified by the calculus would prove to be a great asset for APi-calculus as well as the mobile agentsbased computing in...