The effects of β-ray irradiation on the electrical characteristics of Au/SiO2/n-Si (MOS) structures have been investigated using capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements. The MOS structures were irradiated with beta rays at doses up to 30 kGy. The C-V and G/ω-V characteristics were measured at high frequency (1 MHz) and room temperature before and after β-ray irradiation. The obtained results showed that β-irradiation resulted in an increase in the barrier height ΦB, interface states Nss and depletion layer width WD obtained from reverse bias C-V measurements. In addition, the voltage dependency of the series resistance Rs profile for various radiation doses was obtained from admittance-based measurement method of (C-V and G/ω-V). Both C-V and G/ω-V characteristics indicate that the total dose radiation hardness of MOS structures may be limited by the decisive properties of the SiO2/Si interface to radiation-induced damage. © 2006 Elsevier B.V. All rights reserved.