A properly planned operation for cancer of the mouth often includes the removal of a segment of the mandible or maxilla because oral cancer arises upon these structures or eventually may extend to them. Malignant growths are commoner in the lower than in the upper oral cavity, and the mandible is attacked several times as frequently as the maxilla. The lower jaw is functionally the more important of the two, and resection of it creates a serious defect. A logical plan based upon anatomical and surgical principles and a knowledge of the growth habits of cancer should be used for determining the proper extent of resection without creating needless deformity. This rule should be applied to the individual case rather than treatment being based on routine. The mandible becomes the host of malignant tumor by one of five methods. It is rarely the site of metastasis. Two instances of metastases