Nanotechnology, the science of creating structures, devices, and systems with a length scale of approximately 1-100 nanometers, is poised to have a revolutionary effect on biomedical research and clinical science. By operating at the same scale as most biomacromolecules, nanoscale devices can afford a detailed view of the molecules and events that drive cellular systems and that lie at the heart of disease, and thus, nanotechnology can impact the drug discovery, development, and clinical testing of novel pharmaceuticals. Already, nanoscale drug delivery vehicles are in clinical use, but those successes represent just one way in which nanotechnology will prove useful. One promising nanoscale technology under development may provide real-time, in vivo measurements of apoptosis, and thus may afford an early signal of therapeutic efficacy, both in human clinical trials and in preclinical screening. Microfluidic systems, built of nanoscale components, can enable a host of rapid, massively parallel, high-throughput screening systems, while nanoscale sensors in a wide variety of formats are ready to provide multiplexed biochemical and genetic measurements in living systems. These advances could be utilized to shave time and expense from multiple stages of the drug discovery and development effort.