Risk factors for incident stroke have been examined in middle-aged persons, but less is known about stroke precursors in the elderly, who suffer the highest rates of stroke. Short-term risk factors for incident stroke were examined in a longitudinal, population-based study including extensive measures of subclinical disease. Prospective study of 5201 women and men aged 65 years and older was undertaken in the multicenter Cardiovascular Health Study. During an average 3.31-year follow-up, 188 incident strokes occurred. Stroke incidence increased significantly with age and was similar in women and men. Factors associated with increased stroke risk in multivariate analysis included age, aspirin use, diabetes, impaired glucose tolerance, higher systolic blood pressure, increased time needed to walk 15 ft. frequent falls, elevated creatinine level, abnormal left ventricular (LV) wall motion and increased LV mass on echocardiography, ultrasound-defined carotid stenosis, and atrial fibrillation. Increased LV mass and carotid stenosis were associated with twofold and threefold increases in incidences of stroke, respectively (P < .001). Aspirin users had a 52% higher risk of stroke (relative risk, 1.52; 95% confidence interval, 1.1 to 2.0; P < .007) after adjustment for other factors. This association was present only among aspirin users without prior coronary disease, atrial fibrillation, claudication, or transient ischemic attack, who had an 84% higher risk (relative risk, 1.84; 95% confidence interval, 1.2 to 2.8). Short-term risk of stroke has a complex relationship with aspirin use and is strongly related to subclinical disease in this sample of older adults. These relationships should be considered in assessing stroke risk in the elderly, in whom recognized and subclinical cardiovascular disease is highly prevalent.