In 1993, the Access to Community Care and Effective Services and Supports (ACCESS) federal demonstration program was initiated. Using a quasi-experimental design, the five-year demonstration program sought to assess the impact of integrated systems of care on outcomes for persons with mental illness who are homeless. The authors report on which integration strategies were chosen and how their implementation is quantified. Data collected primarily through annual site visits revealed that only two strategies were used by all nine systems. The system integration strategies employed remained relatively stable over the five years. Successful implementation appears to be related to the strategies selected. (Authors)