Abstract: The conclusions of a Consensus Development Conference on Lowering Blood Cholesterol to Prevent Heart Disease, held December 10-12, 1984 at the National Institutes of Health, are presented in this Conference Statement. A concensus panel of experts in the fields of cardiology, primary care, epidemiology, biostatistics, and preventive medicine was responsible for reviewing available data and drafting the final statement. Panel members addressed the following questions: 1) is there a casual relationship between blood cholesterol levels and coronary heart disease, 2) will reducing blood cholesterol levels help prevent heart disease, 3) at what level of blood cholesterol should dietary or drug treatment be started, 4) should an attempt be made to reduce blood cholesterol levels of the general population, and 5) what research directions should be pursued relative to blood cholesterol and coronary heart disease. A large body of genetic, experimental (animal model), and epidemiological evidence was examined. Panel conclusions include recommendations for 1) drug and dietary treatment of hypercholesterolemia in adults, 2) special guidelines for management of hypercholesterolemia in children, 3) screening strategies for detecting hypercholesterolemia, and 4) a rationale for dietary guidelines suggested for the general population. Research recommendations are outlined in the areas of cellular and molecular biology, clinical investigation, pharmacology, food product development, epidemiological investigation, and community evaluation of nutrition education programs.