Metastases to bone (skeletal metastases) are the most frequent malignant bone tumor. Skeletal metastases can be classified three types;osteolytic, osteoblastic and mixed type. These types depend on the nature of primary cancer. Because imaging studies visualize bone defect and bone formation, these abnormalities can be seen differently depend on the methods to use. In addition, effective therapy to skeletal metastases alters the image. Information of primary cancer and what kinds of treatment have been performed are essential to a diagnosis of skeletal metastasis.