Abstract: A method is described for measuring the noise parameters of field effect transistors (FETs) while still in the wafer stage. Instead of conducting lengthy testing of each individual device at the operating frequency of interest after the devices have been diced, mounted and bonded, each of the devices on a wafer is automatically probed to obtain the standard S-parameters and also the FET's output noise power P.sub.n at a frequency at which parasitic probe effects are avoided. The various noise parameters can then be calculated for higher operating frequencies of interest from FET equivalent circuit parameters derived from the S-parameters, and from P.sub.n, either before or after dicing.