The multi-site evaluation of the federal Serious and Violent Offender Reentry Initiative (SVORI) is assessing the impact on post-release offender behavior of reentry programs funded in 2002–2003 with more than $150 million in federal grant monies. The multi-faceted SVORI programs provide prison- and community-based services and programming to help released prisoners successfully transition from prison to the community. Each program was locally designed and, thus, the programs vary considerably in approach, services provided, and target populations. Although the primary purpose of the multi-site evaluation is to determine the impact of the SVORI programs, an implementation assessment is being conducted to characterize the programs in order to answer the question “impact of what?” This paper provides a brief background on prisoner reentry and the SVORI, and examines the implementation and structure of the 89 reentry programs operated by the 69 SVORI grantees. The findings, based on a program director survey, show that two years following the grant award only 74% of the programs reported being fully operational, and 31% of those reported taking more than 12 months to achieve full implementation. In addition, although most programs are targeting a broad range of offenders, enrollment of participants has proven to be a significant challenge in many sites where enrollments are below expectation. Finally, while most programs reported providing a variety of services and programs to participants, the types and quantities varied considerably among the programs.