The Medicaid Buy-In option promotes employment and economic self-sufficiency for individuals with disabilities. This study used information from federal Medicaid and Medicare databases to examine policy questions about enrollment in the Medicaid Buy-In program in five states and participants' medical expenditures. Using 2001 data, researchers determined the federal databases can be used to generate descriptive information about program participation that states cannot easily provide directly. In addition, information on enrollment patterns and medical expenditures gleaned from the federal databases may be useful to 39;47 in monitoring the Medicaid Buy-In program and to state Medicaid staff developing or refining Buy-In programs.