BACKGROUND: Emergency surgery increases the risk of a retained surgical sponge (RSS) by 9-fold. In most cases, surgical counts are falsely reported as correct. We hypothesized that the institutional costs resulting from a RSS would make routine intraoperative radiography (IOR) more cost-effective than surgical counts in preventing RSS after emergent open cavity cases. METHODS: A cost-effectiveness analysis was performed to compare routine IOR with surgical counts after emergent open cavity operations. Parameter estimates were obtained from the literature, expert opinion via a standardized survey, and existing institutional data. RESULTS: Routine IOR was the preferred strategy ($705 vs $1155 per patient) under the assumptions of the base case. The surgical count strategy was dominated by the institutional costs incurred after a RSS. Routine IOR was preferential as long as the sensitivity of surgical counts was less than 98% and the legal fees were more than $44,000 per case of RSS. CONCLUSIONS: Routine IOR is a simple, cost-effective option to reduce the occurrence of this preventable medical error. Institutional costs and legal fees associated with RSS dominate the cost of the surgical count strategy, making routine IOR a more cost-effective strategy than surgical counts given the best available parameter estimates.