Craniopharyngiomas are usually confined to the sellar and suprasellar regions; infrasellar craniopharyngioma is rare. From an embryological point of view, this unusual localisation can be explained by Erdheim's theory that these tumours can arise anywhere along the craniopharyngeal canal (CPC). However, there has been no proof of this theory, because the CPC is usually obliterated during the 12th week of gestation. I present a case of supra- and infrasellar craniopharyngiomas with a persistent CPC. Imaging demonstrated an intimate relationship between the infrasellar tumour and the CPC, supporting Erdheim's view.