One of the primary targets of the TROPOspheric Monitoring Instrument (TROPOMI), which was launched on 13 October 2017 on-board the Copernicus Sentinel-5 Precursor satellite, is to provide measurements of the total column concentrations of carbon monoxide (CO) in the atmosphere with daily global coverage and a high spatial resolution up to 5.5 × 7 km2. SRON, the Netherlands Institute for Space Research, developed the Shortwave Infrared CO retrieval (SICOR) algorithm that infers CO columns simultaneously with effective cloud parameters from TROPOMI’s 2.3 μm measurements and is deployed by the European Space Agency (ESA) for the near real-time and offline processing of TROPOMI data. Already early in the mission, the TROPOMI CO data set was validated with reference measurements of the Total Carbon Column Observing Network (TCCON), the Infrared Working Group of the Network for the Detection of Atmospheric Composition Change (NDACC-IRWG), and the Measurements Of Pollution in the Atmosphere (MOPITT) and inter-compared with the calculation of the European Centre for Medium-Range Weather Forecasts (ECMWF) assimilation system (ECMWF-IFS). The overall conclusion is that the TROPOMI CO data set is well within the mission requirements of 10% precision and 15% accuracy, and so the product was released by ESA for public access via the Copernicus Open Access Hub (http://www.tropomi.eu/data-products/carbon-monoxide). The TROPOMI CO data set proves useful to track the transport of air pollution on regional and global scales. The high signal to noise ratio of the measurements additionally allows to monitor pollution hot spots like cities, main traffic roads, and plumes from industrial activities, e.g., steel plants and biomass burning events using data from individual satellite overpasses.