Of the nine patients included in this study, five with proven unilateral parotitis initially had diffuse high uptake of 99mTc-pertechnetate in the affected glands with adequate washout following vitamin C stimulation. Of four patients with proven Warthin's tumor, two had focal high uptake in the parotid masses and two had diffuse high uptake on baseline images. All tumors were clearly delineated after stimulation. 99mTc-pertechnetate salivary scintigraphy with vitamin C stimulation may provide a useful tool in differentiating unilateral parotitis from Warthin's tumor.