Background: Although the subspecialty of regional anesthesiology has become an important focus during residency training, there are many factors that might influence a resident9s experience in regional anesthesia (RA). There are few data examining the utilization of regional techniques in an anesthesiology residency program. We undertook a prospective observational study to determine the frequency and reasons for not choosing RA in cases for which it was considered an option. Methods: All scheduled operative procedures that were amenable to neuraxial or major peripheral regional anesthetic techniques were surveyed. Data recorded included the type of intraoperative anesthetic used, type of anesthesiology faculty performing the regional block (regional anesthesiologist vs general anesthesiologist), and reasons for not choosing RA when a regional anesthetic technique was feasible. Results: Of the 2301 surgical procedures amenable to a regional technique, 839 (36.5%) involved use of regional anesthetic, and 1462 (63.5%) involved only a general anesthetic. Of the subjects receiving RA, 32% were performed by general anesthesiology faculty, and 68% were performed by regional anesthesiology faculty. The most common type of regional anesthetic performed by the general anesthesiology faculty was neuraxial blockade (95.2%) (vs 52.5% by regional anesthesiology faculty). Of the cases not involving RA, the reasons were anesthesiology related (40%), surgeon related (34%), patient related (12%), and medical contraindication related (14%). Conclusions: Our prospective observational study suggests that anesthesiology-related reasons may be an important factor for not undertaking these techniques. Although we did not specifically examine the effect on resident education, our study does provide some evidence to support program directors and department chiefs to set up their regional rotations with faculty most likely to perform RA.