To investigate the artefacts in oral biopsies taken by general dental practitioners (GDP) and oral and maxillofacial surgeons (O&MF) and to assess the concordance of clinical and pathological diagnoses. Cross-sectional investigation. Primary care and hospital practice. A total of 354 randomly selected oral biopsy samples studied by the same pathologist. Clinical and pathological diagnoses - prevalence and location of surgical handling artefacts: crush, splits, haemorrhage and fragmentation. Artefacts identified in GDPs biopsies: crush 27.1%; haemorrhage 19.8%; splits 11.3%; and fragmentation 6.2%. O&MSs biopsies showed: crush 10.2%; splits 13%; fragmentation 2.3%; and haemorrhage 8.5%. No differences in split or fragmentation were identified between GDPs and O&MSs. Crush (chi2 = 16.76; P = 0.000) and haemorrhage (chi2 = 9.31; P = 0.003) were more frequently identified in GDPs biopsies. Concordance between clinical and pathological diagnoses was excellent ( > 0.75) for both groups in all disorders considered. The elicited clinical knowledge, the quality of the samples sent to the pathologists seem to suggest the advisability for the GDPs to perform diagnostic biopsies.