ITMS (Integrated Greenhouse Gas Monitoring System for Germany) is a research project funded by the Federal ministry of Education and Research and designed to enable Germany to operationally monitor the sources and sinks of the three most important long-lived greenhouse gases (GHG) CH4, CO2, and N2O via independent measurements and modelling approaches. The collaborative project will support data-driven emission verification and in the long-term result in the establishment of an operational GHG monitoring service at the Deutscher Wetterdienst (German Weather Service).