These data represent monthly averaged values of selected variables for the Data Distribution Centre (DDC) of the Intergovernmental Panel on Climate Change (IPCC). (see also http://www.ipcc-data.org/) The model output prepared for IPCC Fourth Assessment climate of the Pre-industrial control experiment (picntrl). These datasets are available in netCDF and GRIB format. A 50-year integration was conducted using 1985 GHG concentrations and restoring to climatological SST, SSS, and sea-ice extent in order to estimate annual mean heat and freshwater flux adjustments. This was followed by a 200-year integration with preindustrial GHG concentrations to allow the model to approximately equilibrate to a preindustrial climate. The end of this integration served as the initial condition for the preindustrial control integration, representing conditions at year 1850. The preindustrial GHG concentrations were taken to be: CO2=288ppm; CH4=792ppb; N2O=275.5ppb; CFC11=CFC12=0. For this experiment there is only one run available. For model output data in higher temporal resulution and more variables visit the web page https://esg.llnl.gov:8443/home/publicHomePage.do.