Epidemiological cancer registers provide insights into the temporal and spatial dynamics of cancer in defined populations. They produce data on current survival rates and make important contributions to etiological research. Cancer registration in Germany is strongly determined by the country's federal structure, with the 16 federal states having in principle decreed 16 different legislations which are basically comparable but differ in relevant details. Thus, in only 13 of the states is the notification of cancer mandatory. The new cancer register for the state of North Rhine-Westphalia, which commenced in July 2005, and that for Baden-Wurttemberg, for which an entirely new legislation was passed in February 2006, are described in more detail. They provide insights into the new elements of cancer registration in Germany, such as obligatory electronic case notification and close interlinking with clinical registers and tumour centres. The foundation of a new association, the Society of Epidemiological Cancer Registers in Germany (Gesellschaft der epidemiologischen Krebsregister in Deutschland, GEKID e.V.) aims at strengthening the collaboration between population-based registers both nationally and internationally.