OBJECTIVES: Estimate the cost of SREs in patients with bone metastases secondary to solid tumours (i.e. breast, lung and prostate). METHODS: This study assessed county-specific HRU (in Germany, Italy, Spain and the UK [EU4]) as attributed by study investigators to SREs (defined as pathologic fracture [non-vertebral fracture, NVF; vertebral fracture, VF], radiation to bone [RB], spinal cord compression [SCC] and surgery to bone [SB]). Cost-conversion was based on country-specific HRU data (inpatient stays, outpatient visits, emergency room visits, nursing home/long-term care facility stays, home health visits and outpatient procedures) collected retrospectively for 90 days prior to enrolment and prospectively for up to 18-21 months. Unit costs were collected from 2010 national sources. GBP were converted into Euros (£1=1.12867 Euro). RESULTS: A total of 478 eligible patients contributed 893 SREs (109 NVF, 48 VF, 585 RB, 61 SCC and 90 SB) during the study period which, were used for cost conversions. Mean cost per NVF across the EU4 ranged from 1720€ (Germany) to 3209€ (Spain). Mean cost per VF was lowest in the UK (1015€), was more than twice as costly in Germany and Italy (2100€) and highest in Spain (6968€). In the UK, mean cost per RB was about 3 times lower and cost per SCC was approximately twice as costly relative to the other European countries. Mean SB cost was 3348€ in Italy and 4263€ in Spain and was twice as costly in Germany and the UK. Cost variation was linked to the type of HRU and differences in local unit costs. CONCLUSIONS: All SREs are associated with substantial costs and cost per SRE type varied depending on the type of HRU and local unit costs. Preventing SREs in patients with bone metastases may help to reduce the financial burden to the European healthcare systems.