The 40 program clients evaluated had significant trauma histories, showed signs of mental health improvement over the course of program participation, and reported a reduction in substance use. A reduction in both the type and number of criminal justice system contacts was found for clients who remained in treatment for a longer period of time. The program described was developed by Chesterfield County (Richmond, VA metro area). Following confirmation of the need for a jail diversion program that addresses the needs of substance-abusing and mentally ill offenders, a small planning group met to discuss the specifics of the program. The planning group included representatives from the criminal justice system and treatment systems (both substance use and mental health). Due to the success of an existing county Day Reporting Center (DRC) the planning group decided to use the DRC model for the new program. The jail diversion program created, known as the Dual Treatment Track Program (DTT), is a highly structured and intensive regimen of supervision and treatment. The services offered to defendants include an immediate evaluation by a psychiatrist, medication management, entry into intensive outpatient services, drug testing, and pretrial supervision. The target population is offenders who remain in jail and have a dual diagnosis of substance use and mental health disorder. Participants must be at least 18 years old, have a nonviolent criminal history and current charge, and be willing to participate in the program. The program is for both men and women. The three primary data sources for the evaluation were person tracking, client progress/status information, and official statistics. 13 tables and 47 references