Oscillations in the MIM conductance derivative versus bias voltage due to impurity levels in the insulator are analysed by means of a stationary resonance model recently proposed by the authors. Current sensitivity and oscillation shape are determined, emphasizing their temperature dependence. From these results and taking into account the oscillation asymmetry, the position of the impurity level is obtained. The results are in agreement with experimental data on Al-Al2O3-Pd structures. © 1980, All rights reserved.