Although international medicines regulators adopt a common system to assess the safety and efficacy of new drugs, pre-market evaluation is recognized as incomplete given the much larger post-market experience to follow. Adverse drug reactions contribute to more than 100,000 deaths in the United States annually and are among the top 10 leading causes of death. Regulators are developing active surveillance approaches to assess the risks of medicines in the post-market phase to enhance passive adverse drug reaction reporting systems that capture only one to ten percent of ADRs. The objective of this study is to compare international approaches to active surveillance and the manner in which regulatory agencies access and use post-market evidence in their decisions. A conceptual framework is used to guide the comparative analysis of pharmacovigilance governance and policy in the United Kingdom, France, the European Union, the United States and Canada using data gathered from key informant interviews and document review. While research networks are emerging internationally, we found a greater reliance on industry funding and oversight of post-market research in Europe compared to an emphasis on publicly funded programs in North America.