Esthesioneuroblastoma or olfactory neuroblastoma, is a rare tumour. It was first described by Berger et al. in 1924. Since then, approximately 250 cases have been reported. These neuroendocrine neoplasms are rarely associated with hormone excess syndromes. We report a case of olfactory neuroblastoma initially manifested with a syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in a 27-year-old man. A literature review is briefly presented.