This paper presents a new generalized approach to determine the plasma frequency of wire media based on either simulation or experiment. The Loss Factor as a new parameter is determined from reflection and transmission coefficients of finite wire array which is function of frequency and dimensions of the wire array. Plasma frequency is determined by observing the behaviour of loss factor with respect to frequency. Results have been validated by comparing with previously reported results. The present method can be easily extended for any other negative permittivity mediums used for metamaterial realization. © 2011 IEEE.