Clinical decision support (CDS) implemented as part of an electronic medical record (EMR) has a well-documented history of improving patient safety and quality of care; however, the difficulties of keeping CDS up to date have also been documented. At Partners HealthCare, we initially implemented CDS reminders in our 'homegrown' EMR system as 'hardcoded' rules. The challenges of updating existing rules and implementing new rules in the hard-coded state, however, soon made this model unsustainable. After evaluating our needs and requirements for rule creation and maintenance, we designed and created a browser-based rule editor that would decrease turnaround time for logic changes, allowing us to respond to CDS requests more efficiently. We have been able to maintain the older reminder rules with the rule editor, and have added a number of new reminders. Our work to date has confirmed the strengths of the editor, but has also identified a few limitations.