The present biological profile of the adenomatoid odontogenic tumour represents an updating of the data published by the authors from 1990 to 1996. Several new facets of this tumour appear from the approximately 250 cases having been published in recent years. Papers on peripheral variants, AOT-CEOT combined lesions, pigmented AOTs, cases exhibiting tubular dentin induction, new immunohistochemical and ultrastructural data are among the findings having increased our understanding of this interesting tumourous growth. However, the present updating did not in any way change our conception of the unique clinical, radiographical and histological features of the AOT but rather totally confirmed it.