The Canadian constitution divides the responsibility for pharmaceuticals between the federal and provincial governments. While the provincial governments are responsible for establishing public formularies, the majority of the safety and efficacy information that the provinces use comes from the federal government. We interviewed drug plan officials from eight of the ten provinces and two of three territories regarding their views on the Canadian drug safety system. Here we report on the following categories: the federal drug approval system; the strengths and weaknesses of the federal system of postmarket pharmaceutical safety (i.e., pharmacosurveillance); resources available to support provincial formulary decision making; provincial roles in pharmacosurveillance; how the drug safety system could be improved; and the role of the Drug Safety and Effectiveness Network, a recently established virtual network designed to connect researchers throughout Canada who conduct postmarket drug research. Next, we place the Canadian system within an international context by comparing informational asymmetry between government institutions in the United States and the European Union and by looking at how institutions support each other's roles in sharing information and in jointly developing policy through the International Conference on Harmonization. Finally, we draw on international experiences and suggest potential solutions to the concerns that our key informants have identified.