The goal of this study was to characterize antimicrobial prophylaxis and infection surveillance practices at centers treating patients with extracorporeal membrane oxygenation (ECMO). A 37-question web-based survey was sent to all ECMO coordinators and directors at Extracorporeal Life Support Organization (ELSO) participating centers. Data were reported by center. The most complete response was used when multiple surveys were returned from a single center, and respondents' answers from the same center were analyzed for concordance. Responses were obtained from 76% of ELSO centers (132/173) and 41% of survey recipients (223/548). Most centers administer antibiotic prophylaxis (74%, 97/132), and almost half have a standardized protocol (49%, 64/132). Routine antibacterial but not antifungal prophylaxis is common (42%, 62/132 vs. 2/132, 2%). There is significant variation in the antibiotic choices and duration of prophylaxis, regardless of whether the center has a protocol or not. Almost half of centers (49%, 64/132) perform routine surveillance cultures but at variable intervals. There is significant heterogeneity in antibiotic prophylaxis and infection surveillance practice patterns among ELSO centers.