This experimental work is focused on the study of residual stress in thin films deposited by Chemical Vapor Deposition (CVD) techniques and used for the fabrication of micro-electromechanical systems (MEMS) sensors and actuators. The research activity has been carried out in the STMicroelectronics site located in Agrate Brianza (MB), working within the R&D MEMS process and technology development team. The activity has been focused on the fabrication of MEMS test structures, processed inside the ST clean room on 8” wafers, the stress characterization and the discussion of the results. Residual stress of thin films is a critical aspect which has to be carefully taken into account during both design and manufacturing of MEMS devices.