The ECMWF Re-analysis project (ERA40) provides a state of the art and consistent time series of the state of the atmosphere over the past 40 year. This is achieved by using a recent version of the ECMWF analysis-forecasting system over this period. A set of 11 year of data (1986-1996) from the Cabauw Experimental Site for Atmospheric Research (CESAR) has been prepared including profiles of wind, temperature and humidity up to 200 m and surface fluxes of radiation, momentum and sensible-, latent- and soil heat flux. Since July 1994 a windprofiler/RASS system is operational in Cabauw giving, on the average, wind profiles up to 3.5 km agl. and virtual temperature profiles up to 750 m agl. The latest ECMWF model version has an increased vertical resolution so the structure of the atmospheric boundary layer is resolved in much more detail then with the previous re-analysis ERA15. Since Cabauw data has not been used in the assimilation proces of ERA40 they can be used for an independent evaluation. A comparison will be presented of ERA40 atmospheric boundary layer profiles and surface fluxes for the model grid point Cabauw with the long term profile and surface flux observations from Cabauw.