Traditional "one-patient-at-a-time," doctor-centered primary care practice models do not achieve optimal immunization rates for pneumonia and influenza, in part because of time pressures and competing demands from a burgeoning list of clinical guidelines. Some widely used quality improvement methods (physician education, provider feedback, academic detailing, etc.) have only a modest and short-lived impact on improving immunization rates. Evidence is mounting that practices can substantially improve immunization rates by changing practice systems and processes with standing orders and algorithms, expanded nurse decision-making, patient education and incentives, and partnerships with community-based pharmacies. Quality-focused, constantly-learning practices that cultivate a culture of excellence will be most effective in adopting such changes.