The vast majority of prisoners released in the United States are released “conditionally” under some kind of post-release supervision scheme, generally referred to as parole. The goal of parole is two-pronged: to prevent future offending and to provide a social service by engaging ex-prisoners in pro-social activities. The current research posed three main questions: (1) how do prisoners released with and without supervision differ in terms of demographics, incarceration characteristics, and criminal histories (2) do prisoners released with and without supervision differ in terms of re-offending rates; and (3) when and for whom does post-release supervision make the most impact? Relying primarily on Bureau of Justice Statistics data on 38,624 prisoners released in 1994 from 15 States, this analysis found that overall parole supervision had little impact on re-arrest rates of released prisoners. Additionally, it was found that certain types of prisoners benefited more from post-release supervision than others; females and offenders with limited criminal histories were less likely to re-offend if supervised following release. Most supervised prisoners were male drug, property, or violent offenders; it was discovered that of this group, only property offenders benefited from parole supervision. Given the United State’s enormous investment in post-release supervision, the current findings raise questions as to the wisdom of this investment and certainly warrant future study. Figures, tables, endnotes