This report presents findings from a fiscal impact study of the Allegheny County Mental Health Court (MHC) Program. We acquired and linked individual-level data on 365 MHC participants from six state and local public agencies to generate a combined data set that included all relevant criminal justice, mental health, and welfare (cash assistance) utilization. Comparison conditions were constructed to determine the net savings or increase in expenditures of the MHC program as compared to routine adjudication and processing. The results indicate that the MHC program is diverting mentally ill offenders into treatment. In the first year, decreased jail expenditures approximately offset increased costs of treatment. The findings also suggest that, over a longer time frame, the MHC program may result in a net savings to taxpayers. Prospective tracking of participants would be needed to quantify clinical outcomes, as well as to clarify which conditions and offenses MHC supervision most effectively addresses.