OBJECTIVE: A cost-benefit analysis was conducted to compare the costs associated with operating a poison center to the benefits derived from center availability. METHODS: Costs were measured as the direct cost of operating the center, including personnel, reference sources for clinical information, equipment, and administrative overhead expenses. Benefits were measured as the opportunity cost of alternative treatment strategies had a poison center not been available to callers. Data were collected through a concurrent telephone survey of poison center callers at the time of the initial poison exposure call. Callers were asked a series of three questions regarding actions they would have taken if the poison center were not available. Follow-up calls were used to assess actions callers actually took after calling the center. Inputs and benefits were valued using average local prices for medical services from a state paid claims database. A decision analysis model was constructed to calculate the expected cost of poison treatments under two scenarios (poison center available or not). Model probabilities were derived from the percentage of callers indicating that they would pursue a particular course of action. RESULTS: A total of 1695 poison exposure cases were included in the analysis. The average cost per poison exposure associated with not having a poison center available was $62.40. This figure represents the benefit of having a poison center. The average cost of managing a poison call was $8.52, yielding a benefit per call ratio of $7.32. This ratio reflects the amount of additional health care expenditures avoided per dollar expended in a poison center consultation. A sensitivity analysis was conducted to assess the impact of changes in emergency service use on the model. CONCLUSION: Based on our analysis, the immediate information and treatment advice available through a state-run poison center has as a positive societal value.