Recent advances in thin film micromachining techniques have spurred a new generation of smart systems incorporating micro-electromechanical systems (MEMS). Extracting the mechanical properties of MEMS devices has always been a challenge in terms of test time and test cost due to difficulties associated with accurate characterization of thin films. This paper describes a novel technique for diagnosing the mechanical parameters of a cantilever-beam accelerometer using purely electrical test stimulus. The beam is stimulated with an optimized test stimulus, generated by a gradientbased search method. The response measurements made on the MEMS device are mapped to the mechanical properties of the beam using a regression-based mapping technique. Using this method, the mechanical parameters associated with the beam can be estimated within an accuracy of 5% of their actual values. In addition, the test approach is amenable to a compact Built-In Test solution.