The frequency dependence of A.C. conductance of organic solid thin films have been discussed. It is pointed out that the dependence of conductance on the square of frequency is an artifact due to the electrode contact resistance and the capacity of the film. In this paper a method of an added external resistance is proposed to evaluate the electrode contact resistance and thereby the experimentally measured frequency dependences of conductance and capacity of the film could be corrected for the effect of electrode contact resistance. In order to characterize the A.C. conductance of organic solid thin films three parameters are suggested. That is, the D.C. specific conductance σd.c. at extremely low frequencies, the exponent n in the expression σ(f)∝fn for the region of higher frequencies and the value of fx at which the straight line on the lgσ-lgf plot intersects the horizontal line σ=σd.c. For a solution cast film of poly-vinylcarbazole (PVK)-2,4,7-trinitrofluorenone (TNF) (1:0.75) charge transfer complex and an evaporated film of copper phthalocyanine (PcCu) the following results were obtained:PVK-TNF(1:0.75):σd.c.=1.9·10-16(Ω·cm)-1,n=0.96,fx=6.1·10-3Hz at 14℃, PcCu: σd.c.=1.6·10-9(Ω·cm)-1,n=1.2,fx=1·105Hz at 17℃.