A new class of materials: Au-based nanograined metallic glasses (NGMGs) were synthesized using magnetron sputtering with powder targets. A detailed study by x-ray diffraction and high-resolution transmission electron microscopy (TEM) documents the unique nanoscale granular structure of the Au-based NGMG. This material inherited the good mechanical properties of metallic glasses, showing a high hardness of ∼5.3 GPa and a low elastic modulus of ∼79 GPa. In addition, in contrast to most MGs the nanoglassy particles can deform along the loading direction, exhibiting unique tensile elongation up to 100%. During thermal crystallization of NGMG material, even smaller sized Au solid solution nanocrystals are formed within the glassy nanograins, offering a new way for production of the nanocomposites with tailored structural length scales.