INTRODUCTION: Approximately 65-75% of patients with metastatic breast cancer (mBC) suffer from bone metastases (BM). Complications include pain, impaired mobility, hypercalcemia and pathologic fractures, affecting quality of life and prognosis. The epidemiology of breast cancer is well documented. Data on the incidence and prevalence of BM subsequent to breast cancer are scarce. OBJECTIVES: To develop a disease model to estimate the number of women with BC and BM due to BC in the United Kingdom from 2010 to 2020. METHODS: A four-stage incidence-based disease model (non-mBC, mBC, death from BC, death-other causes), simulating the progression of BC was developed to estimate the incidence and prevalence of mBC and BM in the UK. It was run over 50 years using a 1-year cycle length.  Inputs were obtained from published sources. Validation used UK national statistics on number of cases / deaths with BC. After validation, a BM-component was fitted within the BC model to ensure consistency with UK national statistics and to obtain estimates of the future incidence and prevalence of BM from BC in the United Kingdom. RESULTS: New cases of BC in the United Kingdom are predicted to reach ~53,500 in 2020. Deaths due to BC are expected to decrease from ~15,750 to ~11,300 deaths in 2020. Cases of mBC will likely remain stable at ~25,500 cases. Assuming a 54% prevalence of BM in mBC, a RR of 1.42 for survival with-BM versus other-BM, the number of women with BM is assumed to remain stable at ~14,000.  CONCLUSIONS: This model provides new data for BMs in BC. Predictions are in line with expectations from official sources. The model shows that a substantial number of women with BC will develop BM.  Because of the large female population living with mBC, a significant opportunity remains to improve outcomes in patients with BM.