Sociologists of science have noted that the institutional cultures and practices of research tend to de-emphasize the risks produced in the lab, resulting in injuries and deaths in recent lab accidents and increased dangers for surrounding communities. In response to these accidents, science ethics and policy increasingly focus on risk management. One strategy to confront these problems is to implement more procedural safeguards, but ethnographies of science suggest that procedural forms can have the unintended effect of contributing to complacency. What is also needed is a focus on the character of the individual researcher who acts under conditions of risk, such as that provided in virtue ethics. This article shows how prudence can help to meet the problem of risk and how contemporary ideas of risk can reshape understandings of prudence. By so doing, it also suggests ways to encourage sensitivity to risk in the moral education of contemporary scientists.