We conducted a study to estimate the number of mastoidectomy procedures performed annually in the United States. Our results are based on state-specific healthcare utilization data and Medicare-funded procedural data from 2002. The utilization data were obtained from the State Ambulatory Surgery Database, which is made available through the Healthcare Cost and Utilization Project. Statistical Package for the Social Sciences (SPSS) statistical software was used to quantify the number of mastoidectomy procedures performed during 2002 in Maryland, New Jersey, New York, and Florida. Information was also obtained from the Federated Ambulatory Surgery Association on the number of Medicare-funded mastoidectomy procedures performed in 2002. State and U.S. population statistics were obtained from the U.S. Census Bureau. These data were extrapolated to obtain a nationwide estimate of the number of mastoidectomies performed annually in the U.S. With 99% confidence, we determined that 0.73 to 0.94 mastoidectomy procedures were performed per 10,000 population in Maryland and 2.55 to 2.74/10,000 in New York. Estimates for both New Jersey and Florida fell in between. Medicare patients underwent between 1.68 and 1.79 procedures per 10,000 population. Based on these data, we estimate that between 30,000 and 60,000 mastoidectomies are performed each year in the U.S., although we suspect that our range may be an underestimation of the actual number because of some limitations inherent in the data collection process. Although mastoidectomy is a common outpatient procedure, to the best of our knowledge, no report on the annual frequency of mastoidectomy procedures in the U.S. has ever been published in the English-language literature. We hope that our report will serve to motivate further research into technological and surgical advancements surrounding this procedure.