This report presents an unusual case of asymptomatic sialolith of the submandibular gland. A 61-year-old man was referred to our department for multiple extractions. An ortopantomographic exam revealed the existence of a large radiopacity in the right premolar mandibular region. The patient was completely asymptomatic and no episodes of pain and swelling had occurred in the previous years. Ultrasonography and clinical examination confirmed the diagnosis of sialolithiasis of the submandibular duct. The calculus was removed trans-orally in local anaesthesia. The sialolith measured 22 mm and it was mainly constituted by phosphate, calcium and smaller amounts of magnesium. The bacteriological exam revealed the presence of Streptococcus Mitis, Streptococcus Salivarius and non-pathogenic Neisserie. Postoperative course was uneventful. Even a sialolith of significant dimensions may not be symptomatic. Nevertheless, the likelihood of future complications may constitute an indication for surgical removal of abnormal asymptomatic sialoliths.