Diabetes is emerging as a major focus of public health efforts in the United States and worldwide because the burden of the disease is increasing rapidly. The increasing prevalence of diabetes is alarming because of the broad spectrum of acute and long-term complications that typically occur in combination and lead to extensive disability and substantial mortality, while imposing substantial human and economic costs on individuals, families, communities, health care systems, and society. Diabetes management was once considered the domain of the physician-patient relationship, guided by basic science and clinical research. Research focused on the physician-patient relationship is now being complemented with risk reduction media campaigns, health services research, and community-based participatory research. This article summarizes key scientific studies of primary, secondary, and tertiary prevention that provide evidence that diabetes complications can be prevented and controlled. We also discuss how findings from large-scale randomized clinical trails support the critical need for complementary public health approaches to address and eliminate persistent health disparities, using health systems, health communications, and community intervention research and practice.