A state diabetes commission and university diabetes program in Kentucky jointly studied the social and economic impact of diabetes mellitus and its complications on the Commonwealth. This investigation revealed that diabetes was a more serious public health problem than previously supposed. Active, diagnosed diabetes afflicts 4.4% Kentucky's population. Less severe clinical and "borderline" forms of diabetes affect an additional 2.4%. Diabetes is especially prevalent in Appalachian regions and in rural, Western Kentucky. In contrast, its prevalence in Lexington, the second-largest city, is 2.7%, similar to the current, estimated national prevalence. Diabetes is the leading cause of hospitalization by disease, and costs approximately $98,800,000 to $135,000,000. Previous estimates of these social and economic losses were lower, partly because they failed to account for the impact of diabetic complications. An average of 5.23% of all hospitalized Kentuckians have diabetes. Specific services for diabetes care, including organized patient education programs, social or psychological counseling, and preventive foot care, were offered by less than 8% of accredited Kentucky hospitals. This study demonstrates the disparity between need and available services, particularly preventive services, for diabetes care in the health care system.