Au-Cu alloy electroplating is a promising method for fabrication of micro-components used in MEMS devices. Micro-mechanical properties of Au-Cu alloy films fabricated by galvanostatic electroplating are reported in this study. Influences of the current density on surface morphology, crystalline structure, Cu content, and micro-mechanical properties were investigated. An optimum current density at 6 mA/cm(2) was attained for the effects of surface smoothening and grain refinement as the current density was applied in the range of 2-9 mA/cm(2). Micro-pillars having dimensions of 10 x 10 x 20 mu m(3) were fabricated from the electroplated Au-Cu alloy films by focus ion beam and used in the uniaxial micro-compression tests. The highest yield stress of 1.15 GPa was achieved from the film electroplated at 6 mA/cm(2), which the grain size was about 5.3 nm with Cu content of 12.3 wt%. The high yield stress was a synergistic effect of the grain boundary strengthening mechanism with the solid solution strengthening mechanism. (C) 2017 The Electrochemical Society. All rights reserved.