Bone metastasis is a common complication in patients with advanced cancer. It can increase the risk of severe pain, pathological fracture, and spinal cord compression, which make physical activity remarkably worse. Identification of the molecular mechanisms in the initiation or progression of bone metastasis and development of novel therapeutic approaches are very important. microRNAs (miRNAs) have been known as key players in cancer initiation or cancer progression. Recently, the importance of miRNAs in regulating bone metastasis has been also appreciated. Further understanding of the role of miRNAs in metastatic bone disease will lead to the development of novel diagnostic or therapeutic approaches to bone metastasis.