While the four law enforcement agencies were in different phases of the planning process, there were a number of similar critical issues raised and decisions made in the sites. With the planning for a flu pandemic still in its infancy, the case studies reflect only these agencies' experiences. However, these experiences will give other law enforcement leaders insight into some of the issues that need to be addressed in a pandemic flu plan. Proposed guidelines and planning efforts fall into two primary areas: (1) “external” efforts involving local multiagency planning and (2) “internal” planning which are police department specific and include preparing the department, protecting officers, and protecting the community. Recommendations are presented from the police planning officials who helped develop the flu pandemic plans in each site. These lessons have value in assisting law enforcement and other government officials in the beginning process of writing pandemic flu plans for their communities. While the recommendations are many, they indicate that department officials should focus on developing a flexible plan that builds on current public health recommendations specific to a pandemic flu. Engaging and educating the department, as well as incorporating existing multi-agency planning and emergency response efforts into the plan, will assist in the department’s preparation process. As a result of a symposium on pandemic influenza held in Washington, DC, in 2006, four police agencies were identified on which to conduct in-depth case studies. These agencies were Fairfax County Police Department, VA, Toronto Police Service, Ontario, Canada, Overland Park Police Department, KS, and London Metropolitan Police Service, London, England. This report presents the pandemic flu planning efforts of these law enforcement agencies and summarizes the various approaches taken by the departments and the lessons learned. Figures, appendixes