A case of Pindborg's tumour or calcifying odontogenous epithelial tumour in the included +3 of a young girl is presented. The histogenetic explanation given by the first workers to the earliest cases--origin in residues of the enamel organic matrix--is accepted as the most probable, though it is pointed out that the small number of reported cases make doubt and uncertainty inevitable. An interesting point about the case is that its clinical course was followed for several years after surgery.