The study found significant overlap among individuals served by the three systems. A small proportion of the jail population that is often homeless when not in jail uses homeless shelters and FEMS. By focusing on providing reentry housing for persons when they leave jail, coupled with services to frequent users of FEMS with disabilities, the District of Columbia could reduce recidivism in the jail population while improving public health. The study recommends working through the D.C. Interagency Council in developing or expanding collaborative mechanisms that will improve the transition from jail back into the community so as to avoid homelessness for people with serious disabilities who are at risk for returning to jail. A pilot project should be developed to provide permanent supportive housing to a reasonable number of frequent users of jail and homeless shelters who also have a major mental illness or other serious disability. Such a project should be a collaborative effort of D.C. government agencies, nonprofit housing and service providers, advocates, and members of the target population. The project should establish a definition of frequent users of District services. 1 table and 2 figures