Purpose: This study was done to examine the actual state of influenza vaccination among pregnant women and factors affecting vaccination rate. Methods: Data were collected using self-report questionnaires. Participants were pregnant women who participated in a prenatal education program at an acute care hospital in 2013. Data collected from 218 pregnant women were analyzed using the SPSS 18.0 Program. Results: Only 48.6% of the pregnant women had received vaccination when the influenza was prevalent. Statistically significant factors affecting the influenza vaccination rate among pregnant women were vaccination experience in the previous year, knowledge and attitude about vaccination, and gestation period. Conclusion: Results indicate that the influenza vaccination rate among pregnant women is lower than that of elders, healthcare workers, and patients with chronic diseases, who have been considered to be the mandatory vaccination recipients. Therefore, it is necessary to develop programs and policies which provide information including safety of vaccines for pregnant women and to induce positive attitudes towards vaccination for these women, in order to ultimately improve the vaccination rate.