Malignant tumours of the nasal cavities and paranasal sinuses are uncommon.They constitute less than one per cent of all tumours and less than three per cent of head and neck tumours. Although multiple primary carcinomas of the aerodigestive tract are commonly reported, metachronous maxillary sinus carcinomas are rare. To date, all of these cases reported are of squamous cell origin. The incidence of metachronous maxillary carcinoma involving both sinuses is in the range of 1.4 per cent amongst patients with maxillary carcinoma. We present the first reported case, to our knowledge, of a patient with metachronous adenocarcinoma of the maxillary sinus.