Administrative and pharmacy data bases represent a largely untapped resource for clinical decision support and quality improvement. In this study, we examined the feasibility of using New York State Office of Mental Health (NYSOMH) data bases to develop an automated clinical report to support implementation of schizophrenia guidelines. First we reviewed the structure of existing data bases for capacity and limitations in supporting guideline implementation. Second, we identified schizophrenia guideline recommendations and adherence measures that would be the focus of our implementation. Third, a preliminary report was programmed, based on operational definitions of the guideline recommendations. Finally, we developed user groups to define content and format of new reports, through an iterative process of field testing, feedback, and revision. Our experience suggests that administrative and pharmacy data bases, despite their limitations, can be used to develop guidelinebased clinical decision support tools for schizophrenia with high physician acceptability.