Deep understanding of physical properties of the materials under the inuence of radiation exposure is vital for the effective design of dosimeter devices. Detection of radiation is based on the fact that both the electrical and the optical properties of the materials undergo changes upon the exposure to ionizing radiation. It is believed that radiation causes structural defects (called colour centres or oxygen vacancies in oxides) leading to change in their density on the exposure to radiation. Thin lm technology is considered as cost-effective alternative for a broad range of sensors. However, it is especially attractive for metal oxide lms with melting point below 2000 ‐ C, as a wide range of lms with mixed composition can be produced. The inuence of radiation depends on both the dose and the parameters of the lms including their thickness: the degradation is more severe for the higher dose and the thinner lms. This paper reports on gamma radiation sensing properties of thermally evaporated NbO2 thin lms. These lms were deposited at different deposition rate and pressure. It was experimentally conrmed that the manufacturing parameters of the lms affected their gamma radiation sensitivity.