Stroke occurs most frequently in the morning hours, but the impact of the morning blood pressure (BP) level on stroke risk has not been fully investigated in hypertensives. We studied stroke prognosis in 519 older hypertensives in whom ambulatory BP monitoring was performed, and who were followed prospectively. During an average duration of 41 months (range: 1-68 months), 44 stroke events occurred. The morning systolic BP (SBP) was the strongest independent predictor for stroke events among clinic, 24-h, awake, sleep, evening, and pre-awake BPs, with a 10 mmHg increase in morning SBP corresponding to a relative risk (RR) of 1.44 (p<0.0001). The average of the morning and evening SBP (Av-ME-SBP; 10 mmHg increase: RR=1.41, p=0.0001), and the difference between the morning and evening SBP (Di-ME-SBP; 10 mmHg increase: RR=1.24, p=0.0025) were associated with stroke risks independently of each other. The RR of morning hypertension (Av-ME-SBP > or = 135 mmHg and Di-ME-SBP > or = 20 mmHg) vs. sustained hypertension (Av-ME-SBP > = 135 mmHg and Di-ME-SBP < or = 20 mmHg) for stoke events was 3.1 after controlling for other risk factors (p=0.01). In conclusion, morning hypertension is the strongest independent predictor for future clinical stroke events in elderly hypertensive patients, and morning and evening BPs should be monitored in the home as a first step in the treatment of hypertensive patients.