This paper discusses an arms control simulation that formed a central part of the course, Controlling Chemical and Biological Weapons. Based on the experiential learning approach this simulation sought to (a) provide an active learning context for students to acquire an in-depth understanding of central aspects of biological arms control, and (b) gain an appreciation for the complexities of multilateral diplomacy in general and arms control negotiations in particular. I taught this course in spring 2006 to a group of 16 final-year undergraduate students. The arms control simulation complemented the weekly one-hour lectures and replaced the standard one-hour student-led seminar sessions. At the beginning of the simulation I supplied students with a set of confidential country instructions to approach the simulation, which was subdivided into two negotiating rounds of three sessions each and a drafting exercise towards the end of the semester.