The monitoring of the Earth Rotation Parameters is presently mainly supported by Very Long Base Interferometry (VLBI), Satellite Laser Ranging (SLR), Lunar Laser Ranging (LLR). Among those techniques VLBI only seems able to access to the short variations of the Earth Rotation (ER). In the last few years several simulation were conducted to estimate the potential contribution of GPS to the monitoring of the short term fluctuations of the Earth Rotation Parameters (ERP). All conclude that this method could conduct to results whose the precisions are comparable to that ones obtained by VLBI. Moreover, due to the easiness of data collection and analysis, GPS would be very useful to support the services in charge of ERP predictions.