OBJECTIVE: To estimate the effect of a best-practice alert, a reminder within the electronic medical record on the rate of vaccination of pregnant women against influenza. METHODS: Beginning on October 1, 2008, at the Medical College of Wisconsin Obstetrics and Gynecology Clinic, we added a best-practice alert to our electronic prenatal record. The best-practice alert let the health care provider know at each prenatal visit if the patient had not yet either received vaccination against influenza or voiced an informed refusal. We then compared our 2008-2009 vaccination rate with our 2007-2008 rate. If a patient went unvaccinated, we reviewed her record to determine whether a discussion regarding vaccination was held and, if so, the reason she went unvaccinated. RESULTS: Our 2008-2009 vaccination rate exceeded our 2007-2008 rate, 61% compared with 42%, respectively (P<.001; confidence interval [CI] for the difference in proportions 0.14-0.25). Health care providers documented a higher rate of discussions regarding influenza vaccination in 2008-2009 compared with 2007-2008, 89.5% compared with 49.5%, respectively (P<.001, CI for the difference in proportions 0.35-0.45). In 2008-2009, the most common reason for going without vaccination was an informed refusal. In 2007-2008, most of the medical records of unvaccinated women contained no documented discussion. In 2008-2009, 68.1% of the women whose health care providers documented a discussion accepted vaccination. CONCLUSION: Both our rate of vaccination of pregnant women against influenza and the rate of a documented discussion regarding vaccination increased after implementation of the best-practice alert. We recommend that users of electronic medical records add a best-practice alert to improve influenza vaccination rates. (Obstet Gynecol 2012;119:301-5) DOI: 10.1097/AOG.0b013e318242032a