The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20Gt CO2, equivalent to about 4% of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4Gt CO2, 66% of which have occurred since 1990. Emissions in 2015 were 30% lower than those recently reported by the Global Carbon Project.