Sinoliths are calculi found particularly in paranasal sinuses, the rarest location being the ethmoid air cells. There were previously reported only 4 cases of unilateral large ethmoidal sinoliths (ES), this one being the fifth report. We report here the incidental bilateral evidence in a 34-year-old female patient evaluated in Cone Beam Computed Tomography (CBCT) of minor ES. The left ES, of 1.6 mm2 sagittal size, occupied the suprabullar cell, in front of the ground lamella and behind the anterior ethmoidal canal. The right ES, of 7.6 mm2, was located behind the ground lamella. The radiodensity of each ES was about 1000 HU, their bone quality being thus assessed. This is the first evidence of bilateral and clinically silent ethmoidal sinoliths. Being small-sized and incidentally found, it seems reasonable to consider that ethmoidal sinoliths could have a higher incidence but they are overlooked due to the lack of clinical manifestations.