Ohmic contacts to n-GaN are evaluated by low frequency noise measurements. Ohmic contacts were formed by electron beam evaporation of Ti/Al and their rapid thermal alloying. The electron cyclotron resonance Ar plasma etched surface has a poor Ohmic contact with a typical contact resistance of 8.1 x 10(-3) Omega.cm(2), while the as received surface had a better Ohmic contact with a lower contact resistance of 7.5 x 10(-6) Omega.cm(2). The Ohmic characteristics are monitored by the 1/f noise measurements. Low resistance contacts give the typical 1/f noise characteristics, the amplitude of which increases with the square of the sample current, while high resistance contacts give the linear noise power dependence on the sample current I. We are able to evaluate, therefore, the quality of the electrodes most sensitive by the 1/f noise measurements. Assuming the relevant electron concentration between the electrodes, the Hooge parameter is estimated as alpha(H) = 5.3 x 10(-6) at room temperature.