A forecast impact experiment with a constellation of global positioning system radio occultation (GPSRO) receivers is presented. The constellation includes the six COSMIC/FORMO-SAT-3 satellites, combined with the GRACE-A and CHAMP satellites. It is shown that rising and setting occultations measured with the COSMIC satellites have similar bending angle error characteristics. The GPSRO measurements improve the root mean square (rms) geopotential height forecast errors at 500, 200, and 100 hPa in both the Northern and Southern Hemispheres. The forecast fit to radiosonde temperature measurements in the Stratosphere is also improved.