Parotid tumor is a relatively good prognostic tumor which takes possession of 0.5% of the whole body tumor. However because parotid tumor is usually asymptomatic and then diagnosis and treatment are delayed and also difficult to recognize between benign and malignancy which results in high recurrence rate. the authors carried out sialogram with combined CT or CT-sialogram in 23 patients with parotid mass from March 1984 to October 1987 in order to more precisely evaluate parotid mass. CT-sialogram played a paramount role in 1) detectionof lesion 2) determination of whether the lesion was intrinsic or extrinsic 3) localization of the lesion whithin four arbitary compartment of the parotid gland ie posterosuperior posteroinferior anterior and deep 4) estimation of size 5) assessment of whether the lesion was benign or malignancy. And also CT＆CT-sialogram aided to differentiate between deep lobe mass and parapharyngeal origin mass.