An investigation has been made of the microstructure and the electrical properties of Ag-MgF 2 cermet films, with a high Ag fraction, prepared by vacuum evaporation technique. The results show that the cermet film is composed of mainly amorphous MgF 2 matrix with embedded fcc-Ag nanoparticles. The results also show that the sheet resistance of the Ag-MgF 2 film varies between 200 and 2Ω/ within the composition range of 30-70wt% Ag-MgF 2 , that the percolation threshold occurs when Ag volume fraction reaches about 0.14, and that the TCR of the film is between 220 and 560ppm/ o C within the same film composition range. The positive TCR of the films with an Ag content of 30-70wt% could be related to electrical conduction of a conducting network.