The emergence of nanotechnology, and specifically nanobiotechnology, raises major oversight challenges. In the United States, government, industry, and researchers are debating what oversight approaches are most appropriate. Among the federal agencies already embroiled in discussion of oversight approaches are the Food and Drug Administration (FDA), Environmental Protection Agency (EPA), Department of Agriculture (USDA), Occupational Safety and Health Administration (OSHA), and National Institutes of Health (NIH). All can learn from assessment of the successes and failures of past oversight efforts aimed at emerging technologies. This article reports on work funded by the National Science Foundation (NSF) aimed at learning the lessons of past oversight efforts. The article offers insights that emerge from comparing five oversight case studies that examine oversight of genetically engineered organisms (GEOs) in the food supply, pharmaceuticals, medical devices, chemicals in the workplace, and gene therapy. Using quantitative and qualitative analysis, the authors present a new way of evaluating oversight.