Meteorological and glaciological models of snow accumulation and meltwater runoffare used with European Centre for Medium-Range Weather Forecasts climate analyses, to simulate the current/recent surface mass balance of the Greenland Ice Sheet and its interannual variations. The usefulness of the technique is demonstrated by compar-ison with shallow ice-core data (of net snow accumulation) and passive microwave satellite data (of net runoff). Our method will be used with the forthcoming ECMWF ERA-40 reanalysis to produce a novel dataset of temporal and spatial variations of SMB across the Ice Sheet for the past 40 years. It should help elucidate the cause(s) of recent changes in surface elevation of the Ice Sheet observed by aircraft/satellite laser/radar.