Recent polls indicate that only 15% of Americans accept secular evolution as the cause of human origins and less than 10% possess a functional understanding of evolutionary concepts (Gregory 2009; Newport 2012). Due to various social and psychological barriers to the acceptance and understanding of evolutionary theory as well as a minimal educational focus on evolution, for some Americans visiting institutions of informal education like natural history museums is their only opportunity to obtain scientifically sound information about evolution (Diamond and Evans 2007; Spiegel et al. 2006). Many studies have investigated natural history museum visitors' understanding of evolution but few have examined understanding of human evolution in particular. Data were collected over a five-day period at the National Museum of Natural History in Washington, DC. Ninety-six museum visitors participated in an exit survey in the Hall of Human Origins. Fifty percent of visitors subscribed to young earth creationist or theistic evolutionary beliefs. Visitors’ answers to questions pertaining to information presented in the exhibition and their understanding of the principles of evolution as the basis of human origins were scored for accuracy. Relationships were found between acceptance and understanding, with those who accepted secular evolution scoring on average 79%, those who accepted theistic evolution scoring on average 70%, and those who accepted young earth creationism scoring on average 41%. Results indicate that visitors held several misconceptions about evolution, e.g. new traits that arise in populations are always beneficial (54%) and adaptations arise in response to need or an intentional effort to change by individuals (68%). Because natural history museums house the objective scientific knowledge and fundamental evidence for evolution, they play an important role in educating the public. However, as these results indicate, personal beliefs influence visitors’ ability to understand the principles of evolution as the basis of human origins.