Ethmoid sinus osteomas are uncommon, benign, osteogenic tumors. The purpose of this retrospective study was to describe their usual clinical presentation and to discuss their surgical management. The medical records of 25 patients treated for ethmoid osteoma between March 2001 and December 2010 were retrospectively reviewed. The average tumor size was 18.5 ± 14 mm. Only 3 patients were asymptomatic, 14 had a history of frontal sinusitis (complicated with orbital cellulitis in 4 cases), and 4 patients presented with diplopia. An endoscopic approach was performed in 19 cases, a coronal approach in 4 cases, and a combined approach (endoscopic + coronal) in 2 cases. No recurrence was reported. Ethmoid sinus osteoma can be asymptomatic and detected incidentally on CT scans, but often causes frontal sinusitis and orbital complications. The endoscopic approach offers the possibility of safe removal with cosmetic advantages compared to coronal approach.