NASA's TERRA spacecraft was successfully launched on 18 December 1999. Included in its suite of earth monitoring instruments is the MODerate Resolution Imaging Spectroradiomenter (MODIS), a 36 band high spatial resolution (250 m to 1 km) and broad spectral coverage (shortwave reflected solar through longwave emitted thermal) radiometer which allows unprecedented observations of the earth-atmosphere system. Cloud masking from the MODIS observations are now being produced routinely and distributed to earth system scientists. The paper will present the latest updates to the MODIS cloud mask, results from this cloud detection algorithm, and along with validation using other ground based, aircraft and orbiting instruments.