BACKGROUND:Dysplasia is an important feature of leukoplakia. Because agreement among oral pathologists is poor regarding lesional diagnosis, silver stainable nucleolar organizer regions (AgNORs) as replicatory markers may have a place in objectively characterizing dysplasia in tissue specimens. METHODS:We studied 41 normal oral epithelia, 51 oral leukoplakia (26 dysplastic, 25 non-dysplastic), and 51 cases of squamous cell carcinoma specimens for their mean AgNOR counts. RESULTS:Mean AgNOR counts increased gradually from normal epithelium to non-dysplastic to dysplastic leukoplakia to squamous cell carcinoma. Using ROC analysis, we determined a mean AgNOR count cut-point (2.37) that can be used to distinguish between dysplastic and non-dysplastic leukoplakia. The test had a sensitivity of 75% and specificity of 83% with area under the curve being 88%. CONCLUSIONS:Mean AgNOR count could be a valuable criterion for defining objective parameters for diagnosis/determination of dysplasia distinguishing between dysplastic and non-dysplastic leukoplakia.