[en] The effect of gamma irradiation on two types (superstrate- and substrate-type) of CdS/CdTe photodiodes, which we have proposed as potential photoconducting films for compact image sensors with a field emitter array (FEA), was investigated. A "6"0Co gamma-ray source was employed, and the total gamma irradiation dose was more than 500 kGy. For the superstrate-type structure, the irradiation caused the short-circuit current density (J_S_C) to decrease, probably due to the resulting decreased transmittance of the glass substrate. On the other hand, little degradation of the I -V characteristics or spectral response was observed after the gamma irradiation for the substrate-type structure. These results suggest that, taking into account the decrease in transmittance of the glass substrate, the CdS/CdTe photodiodes have sufficient tolerance to high gamma-ray exposure. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)