PURPOSE: To describe the normal sonographic anatomy of the submandibular duct and to assess the value of sonography in the diagnosis of sialolithiasis of the submandibular gland. MATERIALS AND METHODS: Using continuous injection of saline via a sialography needle, we evaluated the normal sonographic anatomy of the submandibular duct in healthy volunteers (n=5). We also reviewed sonographic findings in 47 patients with (n=29) or without (n=18) stones. In each case, the presence or absence of stone was proved by sialography or surgery. RESULTS: In control subjects, sonography accurately depicted the ductal anatomy of the submandibular glands and its relationship with adjacent tissues. For the detection of stones, sonography had a sensitivity of 86%, a specificity of 100%, and an accuracy of 91%. For ductal dilatation, its sensitivity was 91%, its specificity, 100%, and its accuracy, 94%. In 68% of cases with stones, a circumferential low echoic rim surrounding the stone ("rim sign") was present on sonogram. CONCLUSION: Ultrasound is a useful procedure and could replace sialography in most patients with sialolithiasis of the submandibular gland.