Ultrasonography and sialography of parotid glands were prospectively performed on 30 patients with Sjogren syndrome and follow-up ultrasonography was done on 12 patients. Ultrasonography revealed multiple hypoechoic areas (MHA) 2 mm to 5 mm in diameter within the glands in 43% of the patients with intermediate severity of the disease, either homogeneous or slightly nonhomogeneous parotid glands in patients with early stage of the disease, and marked nonhomogeneous glands in patients with advanced diseases. Follow-up ultrasonography showed MHA in one patient, reduction in nonhomogeneity in another three, and no interval changes in the remaining cases. Pathologic studies suggested that MHA represent enlarged parotid lobules replaced by lymphocytic infiltration. We suggest that MHA are characteristic of Sjogren syndrome and that ultrasonography is useful in following the course of the disease and response to treatment.