The aim of this study was to assess the ability of Tl-201 scintigraphy to differentiate between malignant and benign neck masses. Fifty-eight patients with neck masses, whose diagnoses were confirmed by histological examination, were examined. The sensitivity, specificity and accuracy of Tl-201 scintigraphy were 80%, 96% and 88% respectively; when salivary gland masses were excluded, these values were 87%, 95% and 91% respectively. Our results suggest that Tl-201 scintigraphy is highly reliable in determining the malignancy of neck masses, especially when salivary gland masses are excluded. ((C) 1998 Lippincott-Raven Publishers).