The authors report the results of implementing a diabetes mellitus guideline in a group practice in which uniform, technology-generated care processes were produced for patients, clinical staff, and providers. The objective was to increase the annual rate of recommended tests and examinations for patients with diabetes and to reduce levels of glycosylated hemoglobin, blood pressure, and low-density lipoprotein cholesterol. A process change for type 2 diabetes mellitus was implemented that included changes in office visit structure, protocol-driven electronic prompts for nursing and physician staffs, clinical decision support built into a new electronic medical record form, and audit with feedback. Twelve primary care physicians treated a total of 1592 patients with diabetes between January 2007 and January 2008. There were prompt and statistically significant improvements in 5 process measures and 2 outcome measures; a quality summary measure showed 8% overall improvement. Statistically significant improvements with moderate effect size were observed after a multitiered intervention.