Objectives: This retrospective claim-based study assessed 1-year medical costs associated with second fracture(s) for patients over 50. years old with an initial closed hip, clinical vertebral or non-hip non-vertebral (NHNV) fracture using 2002-2008 MarketScan® Commercial and Medicare Supplemental Databases. Methods: Patients with incident fracture and ≥ 12-month pre-period and follow-up period from the incident fracture were extracted. Index date was the first subsequent fracture date for patients with subsequent fracture during the 12-month (cases); index dates for patients without subsequent fractures during the 12-month follow-up (controls) were randomly assigned based on the distribution of index dates of cases. Total costs were examined during the 12-month follow-up period using generalized linear models. A decomposition analysis of the incremental costs attributable to the second fracture was conducted to examine what proportion of the difference was due to different patient characteristics and what proportion was due to different model structures between cases and controls. Results: For privately insured patients with hip, vertebral, or NHNV fracture, the 1-year second fracture rate was 8.0%, 5.1%, and 4.0%, and 1-year incremental costs were $47,351, $43,238, and $23,852, respectively; for Medicare patients, the corresponding rates and costs were 8.8%, 9.2%, and 8.2%, and $18,645, $19,702, and $19,697. Nationally projected annual cost of second fracture was $834 (95% confidence interval: $763-$914) million for patients with commercial insurance and $1.13 (95% confidence interval: $1.09-$1.17) billion for Medicare patients. Conclusions: The average cost of patients with subsequent fracture(s) was substantial. Effective management of first fractures may help reduce the long-term economic and clinical burden. © 2010 Elsevier Inc.