28 cases of mandibular tumors and cysts, which have been confirmed by operation or biopsy, were reviewed andanalyzed on clinical symptoms, radiologic findings and related references. These 23 cases among 28 cases werediagnosed at Dental College fo Yonsei University, Severance Hospital and 5 cases at Dental College of SeoulNational University Hosital. 1. Among 28 cases, benign tumors were 15 cases, malignant tumors were 7 cases andcysts were 6 cases histologically. 2. The symptoms were insidious onset with bulging mass, spontaneous loss ofteeth, local pain, ulceration with discharge, mastication difficulty, hemorrhage and salivation in descendingorder. 3. The most freqeunt site of the lesion were premolar, molar area of the mandible, body, angle, coronoidand condyloid process of mandible in descending order. 4. Radiological findings of mandibular cysts were cysticbony expansion, sharply demarcated margin with cortical thinning, loss of lamina dura, root resorption, loss ofboney trabeculations, displaced tooth, loss of tooth, normal dental crown in cyst and lobulated cyst. 5. Theradiological findings of benign mandibular tumors were edentulous, thinning of cortex without break down,multilocular cystic bony expansion with scalloped margin, coarse irregular bony trabeculations, loss of laminadura, root resorption, irregular mottled calcification, radiolucent rim, mixed partially cystic bony expansion,bone destruction and sclerotic margin. 6. The radiological findings of malignant mandibular tumors were cortexbreak down. loss of boney trabeculations, irregular honeycombing or granular permeative bone destruction.