Background: The prevalence of oral and maxillofacial pathology has not previously been reported in the Australian adult population. This study aimed to audit a large pathology service to provide insight into the prevalence of head and neck pathologies. Methods: Written records of a major Australian oral pathology service were imported into an electronic database. Age, gender and histological diagnosis were assessed. Prevalence of histological diagnoses as a percentage of the major diagnostic categories and of the whole sample were calculated, as well as gender predilections and mean age of presentation of disease. Results: A total of 6344 oral pathology specimens, collected from adults aged 17 years and over were included in the analysis. Mucosal pathology was the most common pathology (37.2%), followed by odontogenic cysts (16.3%) and dental pathology (14.5%). The three most common histological diagnoses were fibrous hyperplasia (15.2%), chronic periapical granuloma (9.6%) and radicular cyst (9.5%). The male:female ratio of the entire sample was 0.74. Conclusions: This is the first study to describe the prevalence of oral and maxillofacial pathology among adult patients in an Australian population. The trends seen in this study are repeated in studies from other parts of the world, and are of diagnostic importance.