Bone metastasis is a common occurrence in human malignancies, including breast, prostate, and lung cancer, and is associated with a high morbidity rate because of intractable bone pain, pathological fractures, hypercalcemia, and nerve compression. Animal models of bone metastasis are important tools to investigate the pathogenesis and develop treatment strategies. However, there are few models of spontaneous bone metastasis despite the fact that animals often spontaneously develop cancer. Here, we describe methods for developing a mouse model of breast cancer bone metastasis achieved by injection of MDA-MB-231 breast cancer cells into the heart. This assay can be applied to studies on roles of CCN proteins in tumor metastasis and development of treatment strategies targeting CCN proteins.