Coronary heart disease (CHD) was examined as a precursor of stroke based on 24 years of biennial examinations, during which time 344 strokes occurred. Routine ECGs, chest roentgenograms, and BP levels were obtained, CHD and cardiac failure status were evaluated at each examination, and risk of stroke was ascertained. The five major CHD risk factors jointly were actually as predictive of stroke as CHD. The dominant stroke risk factors were hypertension, clinical manifestations of CHD, cardiac failure, atrial fibrillation, and ECG and roentgenographic evidence of a compromised coronary circulation. Coronary heart disease almost tripled the risk of a stroke, and cardiac failure was associated with more than a fivefold increased risk. Angina pectoris carried half the risk of myocardial infarction. Coronary disease and cardiac failure added to the risk of stroke associated with hypertension. Coronary heart disease increased stroke risk in the absence of hypertension or cardiac failure, but risk was greatly augmented when these coexisted.