Objective: Metastatic bone disease (MBD) and subsequent skeletal-related events (SREs) are common complications secondary to solid tumors. We conducted a retrospective analysis of US health insurance claims to examine the cost of SREs among patients with MBD secondary to breast, lung, or prostate cancer. Methods: Data were obtained from i3's Lab Rx Database from May 1, 2000 to March 31, 2005. Patients were included if they had at least two ICD-9 diagnoses of breast, lung, or prostate cancer; at least two diagnoses of MBD; and at least one SRE on or after the initial MBD diagnosis. SREs were defined as a pathological fracture, spinal cord compression, surgery to the bone, or radiation to the bone and were identified using ICD-9 and CPT-4 codes. Patients had to be continuously insured for at least six months prior to their first SRE (index date) and one month after their index date. Descriptive statistics were calculated and the annual cost of SREs was estimated using Kaplan-Meier curves to adjust for censoring. Results: In the study period, 3584 patients were diagnosed with breast, lung, or prostate cancer and MBD, and 1840 (51%) experienced at least one incident SRE. Regardless of tumor type, patients were most frequently found to have radiation therapy (86%-89%) followed by pathological fracture (23%-29%), bone surgery (12%-16%), and spinal cord compression (7%-9%). The adjusted mean costs associated with SREs in the one year after the index SRE ranged from $12,469 to $17,408, with the highest costs associated with radiation therapy ($5,930 to $7,152), pathological fracture ($3,179 to $6,624), and bone surgery ($2,218 to $2,536). Conclusion: This analysis of patients with cancer-related MBD revealed that the incidence of SREs is high and their annual economic impact is substantial regardless of tumor type.