Aim: To analyze the relation between biopsy specimen's size and the definitive diagnosis. In addition, other variables including oral mucosa region, type of disease and general versus specialist practitioner were also assessed.

Methods: Data from specimens submitted to histopathological examination between 2007 and 2017 were retrospectively analysed.

Results: We analysed data on 792 patients. Out of 1089 archived reports, 81 (7.4%) had no definitive diagnosis. Multivariate analysis rendered biopsy length as the factor influencing the possibility to reach a definitive diagnosis.

Conclusion: The size of the specimen is an important parameter to achieve a correct histopathological diagnosis of the oral lesions investigated. According to our results, it seems that a 10 mm length is adequate to optimize the biopsy outcome. No statistically differences were observed between GPDs and oral surgery specialists, probably because biopsies were performed by experienced general practitioners, although not formally trained.