Objective: To describe practices concerning antibiotic prophylaxis for cesarean delivery among maternal-fetal medicine (MFM) physicians in the United States. Methods: A 10-item self-administered survey about their routine use of antibiotics for cesarean delivery was mailed once only to a random sample of 1000 US-based fellows of the Society of Maternal-Fetal Medicine in November 2009. Results: There were a total of 250 respondents from 40 US states between 10/09 and 4/2010, corresponding to a response rate of 25%. Among respondents, 95.5% reported routine use of a cephalosporin only (including 84.4% who reported use of cefazolin) as antibiotic prophylaxis for cesarean delivery; less than 3% reported use of an extended spectrum regimen such as cefazolin + azithromycin. Preoperative administration of antibiotic prophylaxis was reported by 84.6% compared to 15.0% who reported giving antibiotic prophylaxis after umbilical cord clamping. Administration of a single dose of antibiotic was reported by 96%. Conclusion: The majority of MFM specialists in the US report routine and preoperative use of a single prophylactic dose of a 1st generation cephalosporin for cesarean delivery. © 2012 Informa UK, Ltd.