Metallic glasses exhibit generally high hardness and elastic modulus values at the expense of very limited plasticity. The incorporation of crystalline particles within an amorphous metallic matrix has been widely reported to improve the performance of these materials by reducing crack propagation. The present work analyzes the influence of nanometer-size ZrC particles on the nano-mechanical behavior of mechanically alloyed Zr55Cu30Al10Ni5 glassy matrix composites. The volume fraction of ZrC particles ranged from zero up to 20 vol. %, showing a critical change in the mechanical behavior between 10 and 20 vol. %, particularly in the elastic response.