Sjögren's syndrome (SS) is a chronic autoimmune rheumatic disease, which primarily affects the exocrine glands. The diagnosis of SS is based on American-European diagnostic criteria that include, as independent diagnostic items, imaging techniques such as sialography and scintigraphy. In recent years, new imaging techniques--including MRI, magnetic resonance sialography and ultrasonography of the salivary glands--have been used to diagnose SS. Ultrasonography is a noninvasive method that provides information about the changes to major salivary glands during inflammation. In a recently published report by Wernicke and colleagues, ultrasonography revealed decreased echogenicity and volume of submandibular glands in patients with SS but not in normal individuals, with a specificity of more than 90% and sensitivity close to 60%. Nevertheless, this technique should be carefully validated, using disease-control patients with dry mouth and comparison with other diagnostic items. The clarification of these matters will enable the use of ultrasonography for diagnostic purposes in SS.