In a survey of 1500 coronal sinonasal CT scans, 46 patients were found to have paranasal sinus osteomas. The overall incidence was 3%, with a predilection for decades 5 and 6 and a male-to-female ratio of 1.3:1. The frontal sinus was most commonly involved, and of these lesions 37% were in the immediate vicinity of the nasofrontal duct and 21% above and lateral to the ostium. Tumour size varied from a mean diameter of 1.5 mm to 30 mm; however, 17 lesions were 5 mm in size or less. Five matrix patterns were observed. Only two patients were symptomatic and only three osteomas excised. Isotope bone scanning may be a useful screening test with specific follow-up utilising computed tomography.