Digital subtraction sialography of the parotid glands was performed in 34 patients with primary Sjögren's syndrome (SS) and 78 patients suspected of having primary SS in whom the diagnosis could be excluded (NON-SS). The following sialographic features were found more frequently in the patients with primary SS than in the NON-SS patients: a sparse overall branching pattern of the ducts, progressive widening and irregularity of the duct walls, disappearance of a homogeneous parenchyma blush and the occurrence of peripheral acinar dilations. The most discriminating findings between the 2 patient groups were the presence of acinar dilations and the disappearance of the homogeneous parenchyma blush. The sensitivity and specificity of the presence of acinar dilatations were 79 and 95%, respectively. Both the sensitivity and specificity of the presence of an irregular or absent parenchyma blush were 91%. The concurrent finding of acinar dilatations and an irregular or absent parenchyma blush had a sensitivity of 77% and a specificity of 95%. We conclude that digital subtraction sialography is a useful adjunctive diagnostic procedure for primary SS.