28 cases of mandibular tumors and cysts, which have been confirmed by operation or biopsy, were reviewed and analyzed on clinical symptoms, radiologic findings and related references. These 23 cases among 28 cases were diagnosed at Dental College of Yonsei University, Severance Hospital and 5 cases at Dental College of Seoul National University Hospital. 1. Among 28 cases, benign tumors were 15 cases, malignant tumors were 7 cases and cysts were 6 cases histologically. 2. The symptoms were insidious onset with bulging mass, spontaneous loss of teeth, local pain, ulceration with discharge, mastication difficulty, hemorrhage and salivation in descending order. 3. The most frequent site of the lesion were premolar, molar area of the mandible, body, angle, coronoid and condyloid process of mandible in descending order. 4. Radiological findings of mandibular cysts were cystic bony expansion, sharply demarcated margin with cortical thinning, loss of lamina dura, root resorption, los of bony trabeculations, displaced tooth, loss of tooth, normal dental crown in cyst and lobulated cyst. 5. The radiological 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 lamina dura 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 cortex break down, loss of bony trabeculations, irregular honeycombing or granular permeative bone destruction.