Nanotechnology and personalized medicine are two of the most rapidly emerging areas of biomedical research, as well as two of the most promising technologies for improving health care and health outcomes. They are also rapidly converging in numerous current and future clinical applications. Examples include the use of nanotechnology for improved DNA sequencing and SNP analysis, the development of nano-therapeutics that can target specific cell and tissue types, biosensors for specific proteins and other molecules in vivo, and point-of-care molecular diagnostic devices enabled by nanotechnology. Nanotechnology offers many advantages for personalized medicine applications, including a size that matches the scale of the molecular substrates of personalized medicine, an increased sensitivity in detecting and binding with target molecules, and flexibility in the design and function of therapeutics and diagnostics at the nano scale. Yet, at the same time, the utilization of nanotechnology in personalized medicine may create uncertainties or risk relating to potential toxicity. In addition to describing the scientific and technical opportunities and challenges in applying nanotechnology to personalized medicine, this article also addresses some of the policy, legal and ethical issues raised by the convergence of nanotechnology and personalized medicine.