Review of data from the California Department of Corrections and Rehabilitation found that inmates sentenced under the State's three strikes law received sentences that were 9 years longer than those given to inmates sentenced for similar crimes not under the three strikes law and that these longer sentences represented a cost to the State of $19.2 billion. The review also found that of the $529 million that the State spent on prison health care services provided by specialty health care providers, $469 million, or 88 percent, was associated with specialty care for individual inmates. Finally, the review found that a significant amount of costs related to custody staff overtime resulted from medical guarding and transportation of inmates. This review by the California State Auditor examined the significant cost increases at the State's Department of Corrections and Rehabilitation that have resulted from the incarceration of inmates sentenced under the State's three strikes law and from inmates receiving specialty health care services. Recommendations from the Auditor's office include: prison health care services should continue to explore ways to reduce the costs of inmate medical care, such as the use of telemedicine and the early release of terminally ill inmates; updating staffing formulas to meet custody staffing needs; and improve communication with policymakers regarding the annual costs of incarceration. Responses from department officials are also included in the report. Tables, figures, and appendixes