Objective: The Illinois Department of Public Health mandated that all clinicians who provide care to obstetric patients participate in the Illinois Obstetric Hemorrhage Project. The aim of the current report is to describe change in knowledge among providers engaged in the project, as assessed by pre- and post-tests.Methods: The project, implemented 2008 to 2010, included four components: a written 25-item multiple-choice examination (pre-test), a didactic lecture, skill stations (for teaching blood loss estimation), and a simulation drill and debriefing. Participants completed a post-test 6 months later. Pre- and post-test examination scores were compared.Results: Data from 95 hospitals are included in this analysis (9456 paired test results). The proportion of participants who scored 88% correct answers increased from 10.9% on the pre-test to 49.1% on the post-test (p<0.0001). Registered nurses made greater improvements in test scores than anesthesia and obstetric providers (p<0.0001).Conclusions: The Illinois Obstetric Hemorrhage Project was successful in improving knowledge of obstetric hemorrhage in a large number of providers with different expertise and experience levels. Further long-term study is essential to determine whether the skills acquired during the Project contribute to improved obstetric hemorrhage outcomes for the women of Illinois.