Ambulatory blood pressure monitoring (ABPM) and home blood pressure (BP) measurement appear to be useful in the assessment of the effects of non-pharmacological treatment of hypertension because they can detect small changes in BP without observer bias. We studied the effects of various lifestyle modifications using ABPM and home BP measurement in Japanese patients with hypertension. Weight reduction by a hypocaloric diet (average 4 kg) was associated with decreases in 24-h BP (10/4 mmHg) as well as casual BP (9/6 mmHg). The reductions in daytime and night-time BPs were comparable. The effects of daily walking without weight loss on office, home, and 24-h BPs were 2-3/1-2 mmHg. The changes in home and 24-h BPs were more significant than those in office BP. A low-salt diet (25 mmol/day versus 250 mmol/day) decreased 24-h BP by 9/4 mmHg. This hypotensive effect was observed throughout the day. Potassium supplementation (64 mmol/day) decreased office, home and 24-h BPs by 3-4/1-2 mmHg. The changes in home and 24-h BPs were highly significant compared with office BP. Supplementation of magnesium (20 mmol/day) also reduced those BPs significantly. However, the effects of calcium supplementation (25 mmol/day) were small (1-2/1 mmHg) and were significant only for home BP. Alcohol restriction for 4 weeks decreased daytime BP by 3/2 mmHg but increased night-time BP by 4/2 mmHg. Average 24-h BP did not change. Smoking cessation lowered daytime BP without affecting night-time BP. Monitoring of 24-h BP and home BP can detect small changes in BP produced by lifestyle modifications. Ambulatory BP monitoring is particularly suitable in the assessment of changes in lifestyle affecting the circadian pattern of BP such as alcohol consumption and smoking.