Currently, the New Jersey Department of Corrections does not provide reentry planning for male inmates with special needs. This required that an estimate of the cost of such programming be calculated by drawing on the experience of reentry and case-management programs operating in other States. Different assumptions were used for the distribution of treatment needs and criminal characteristics within the population of male mentally disordered offenders, ranging from equal treatment needs and placement difficulties to different treatment needs and difficulties in accessing community-based resources due to past criminal behavior. The costs of these investments ranged from about $700,000 to $934,000 per year for approximately 500 released inmates, with costs approaching the lower end of the range if the coordination and supervision period was shortened and standardized. These estimates do not take into account undiagnosed and/or untreated mental illness within the general population of New Jersey prisons. The authors advise that reentry programs serve a single function, i.e., to coordinate community-based services for the purpose of facilitating community reintegration after imprisonment; however, if the community-based services needed by the released prisoner do not exist or are inaccessible to him, then reentry planning will not be cost-effective, but it will expose the gaps in services and treatment that will ultimately influence reoffending behavior. 5 tables and 34 references