Nanoparticles are materials with average particles size less than 100 nm. Due to their smaller particle size compared to macro-sized materials, they have larger surface area that enhances various physical and chemical properties such as mechanical strength, stability, reactivity, solubility, dissolution rate, bioavailability etc. As a result nanomaterials have wide applications in various fields ranging from chemical, pharmaceutical, agro, as well as paint industry. Here in this chapter, we have discussed about scaled up manufacturing of nanoparticles prepared using mechanical milling, their advantages as well as challenges encountered during their preparation.