The electronic density of states in the forbidden gap of polycrystalline silicon has been determined from an analysis of capacitance and conductance of a Metal/SiO2(∼60 A˚)/polycrystalline silicon(∼250 A˚)/Si(111) (MOSS) structure. In this structure the thickness of the polycrystalline silicon is comparable to its grain size. Net density of trapped charges in the polycrystalline silicon is enough to terminate the electric field penetrating from the oxide layer. Then, two‐terminal admittance of the MOSS structure is dominated by charging or discharging of the trapping states in a wide range of applied gate bias. TheU‐shaped distribution of trapping state density has been found for thin polycrystalline silicon films.