BACKGROUND: Panel Management can expand prevention and chronic illness management beyond the office visit, but there is limited evidence for its effectiveness or guidance on how best to incorporate it into practice. OBJECTIVE: We aimed to test the effectiveness of incorporating panel management into clinical practice by incorporating Panel Management Assistants (PMAs) into primary care teams with and without panel management education. DESIGN: We conducted an 8-month cluster-randomized controlled trial of panel management for improving hypertension and smoking cessation outcomes among veterans. PATRICIPANTS: Twenty primary care teams from the Veterans Affairs New York Harbor were randomized to control, panel management support, or panel management support plus education groups. Teams included 69 clinical staff serving 8,153 hypertensive and/or smoking veterans. INTERVENTIONS: Teams assigned to the intervention groups worked with non-clinical Panel Management Assistants (PMAs) who monitored care gaps and conducted proactive patient outreach, including referrals, mail reminders and motivational interviewing by telephone. MAIN MEASURES: Measurements included mean systolic and diastolic blood pressure, proportion of patients with controlled blood pressure, self-reported quit attempts, nicotine replacement therapy (NRT) prescriptions, and referrals to disease management services. KEY RESULTS: Change in mean blood pressure, blood pressure control, and smoking quit rates were similar across study groups. Patients on intervention teams were more likely to receive NRT (OR=1.4; 95 % CI 1.2-1.6) and enroll in the disease management services MOVE! (OR=1.2; 95 % CI 1.1-1.6) and Telehealth (OR=1.7, 95 % CI 1.4-2.1) than patients on control teams. CONCLUSIONS: Panel Management support for primary care teams improved process, but not outcome variables among veterans with hypertension and smoking. Incorporating PMAs into teams was feasible and highly valued by the clinical staff, but clinical impact may require a longer intervention.KEY WORDS: panel management; hypertension; smoking; PCMH. J Gen Intern Med 30(7):916-23