The Centers for Disease Control and Prevention Advisory Committee on Immunization Practices recommends routine influenza vaccination for all women who are or will be pregnant during the influenza season. During seasonal influenza epidemics, during previous pandemics, and with the current influenza A (H1N1) pandemic, pregnancy places otherwise healthy women at increased risk for serious complications from influenza, including death. Inactivated influenza vaccine can be safely and effectively administered during any trimester of pregnancy. No study to date has demonstrated an increased risk of either maternal complications or adverse fetal outcomes associated with inactivated influenza vaccination. Moreover, no scientific evidence exists that thimerosal-containing vaccines are a cause of adverse events among children born to women who received influenza vaccine during pregnancy. In this article, we review the evidentiary basis for the recommendation of vaccination of all women who will be pregnant during the influenza season and safety data of influenza vaccination during pregnancy.