The Centers for Disease Control (CDC), the Consumer Product Safety Commission (CPSC), and the Food and Drug Administration (FDA) collaboratively created this surveillance project to estimate incidence of adverse drug events. The summary describes the evaluation of the system, based on studying reports from a convenience sample of participating hospitals. While the sensitivity of capturing events was low, the positive predictive value that reported events represented in actual cases was high. An editorial note suggests that this reporting system may represent an important, ongoing resource for recording and preventing future adverse drug events.