Nanocrystals (NCs) are a key innovation in nanotechnology, particularly for improving drug delivery systems for poorly soluble drugs. There are various methods employed for NC production, including top-down techniques like pearl/ball milling, and high-pressure homogenization; bottom-up methods like precipitation, and cryo-vacuum techniques; and combination approaches like NanoEdge and SmartCrystal technologies. With these methods, NC’s size, stability, and solubility can be altered. For the physical and chemical evaluation of developed NCs, advanced characterization techniques such as scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and dynamic light scattering (DLS) are crucial. These assessments ensure stability, solubility, and efficacy in drug formulations. NCs are widely used in fields like cancer therapy and treatments for neurodegenerative diseases. Despite their potential, challenges like regulatory concerns, toxicity risks, and large-scale production hurdles exist. In this chapter, an attempt has been made to review and compile recent advances in production and characterization methods of NCs, emphasizing their future role in overcoming biological barriers and advancing personalized medicine.