This study focuses on an organization at the interface of the criminal justice and mental health systems. The institution examined was a maximum security mental hospital, primarily for incompetent felony defendants, as it was attempting to change from a custodial to a treatment orientation. Interest centered on whether structural factors in this type of organization place significant constraints on the ability of the organization to change in the intended direction. Data were collected at five points in time over a two-year period to test the impact of three substantial modifications in the organizational setting on the level of treatment. The latter was measured by patient/inmate responses on Prisonization and Favorableness Scales. Supporting the research hypotheses, there were some initial fluctuations in scle scores, but during the two periods of organizational stability no significant changes in either scale were evident. These findings are discussed in the context of technological constraints facing organizations, especially those providing mental health services in the criminal justice system, with the dual goals of custody and treatment.