Seven diamonds-like carbon (Ag-DLC) films with different Ag contents were deposited on (100) Si substrate in a mid-frequency dual-magnetron system. Studies were performed to investigate the influence of the Ag content and nanograin size on the microstructure and mechanical properties of the films. Results showed: (i) the dispersion of Ag nanocrystallites within the amorphous DLC matrix, and the tendency for the size of the Ag nanocrystallite to increase with the Ag content; (ii) the exhibition of higher hardness, lower intrinsic stress and better adhesion for the films with Ag content ranging between 7.4 and 12.5 at% when compared with the films of Ag content in range of 16.8-24.7 at%; and (iii) the achievement of the best mechanical properties for the film deposited with 9.6 at% Ag. (C) 2009 Elsevier B.V. All rights reserved.