Best evidence from prospective studies with aggressive monitoring suggests that the incidence of needlestick injuries is significantly higher than reported through passive surveillance, ranging from 14 to 839 needlestick injuries per 1,000 health care workers per year. The economic cost of managing these injuries is substantial, ranging from dollars 51 to dollars 3,766 (2002 U.S. dollars). This amount excludes the cost of treating the long-term complications of needlestick injuries, such as HIV and hepatitis B and C infections, each of which can cost several hundreds of thousands of dollars to manage. In addition, health care workers experience significant fear, anxiety, and emotional distress following a needlestick injury, sometimes resulting in occupational and behavior changes. Despite the availability of engineered injury prevention devices, the implementation of these new technologies has been mixed in part because of the perception that these devices are costly and cost ineffective. However, widespread use of safety devices might be more easily justified on economic grounds when the full clinical and economic benefits of these new technologies are considered, especially within the context of injury prevention.