Communicable diseases do not respect national boundaries and are important challenges to health internationally. This article aims to support the improvement and integration of surveillance systems in Europe and beyond by drawing on research comparing national systems. Definitions and concepts of epidemiological surveillance are described as a continuous systematic process that observes and reflects the real situation in society not only within but also across political boundaries. Outbreaks that affect more than one country show that a systematic comparative analysis of surveillance systems in Europe can help improve disease control. National surveillance systems from six European Union countries and from a later comparison of twenty-six European countries are examined. An effective surveillance system can provide information for action and act as a monitoring body for health authorities. Nevertheless, many European surveillance systems still require improvement in the interests of public health.