A new guideline on metabolic syndrome (MS) in Japanese was introduced in 2005. The purpose of this study was to evaluate the prevalence and lifestyle characteristics of Japanese hypertensive patients with MS. Subjects were 290 patients (mean age: 64+/-11 years) who had been followed at our hospital. The waist circumference (WC) and body mass index (BMI) were assessed. Subjects who had BMI >or=25 kg/m(2) were defined as having BMI obesity, while abdominal obesity was defined as a WC >or=85 cm in men and >or=90 cm in women, respectively. Since all patients had hypertension, the definition of MS was made when the patient had abdominal obesity plus either dyslipidemia or glucose intolerance, or both. Among the subjects, 230 patients underwent 24-h home urine collection to measure urinary salt and potassium excretions. Dietary habits were also assessed by use of a questionnaire. Mean values of BMI and WC were 24.2+/-3.4 kg/m(2) and 87.1+/-9.6 cm, respectively. Among the total subject group, 39% patients were classified as having BMI obesity, 49% as having abdominal obesity, and 27% as having MS. BMI was significantly correlated with WC both in men (r=0.86; p<0.01) and in women (r=0.79; p<0.01). More men than women belonged to the BMI obesity (46% vs. 33%, p<0.05), abdominal obesity (63% vs. 39%, p<0.01) and MS (39% vs. 18%, p<0.01) groups. There were no significant differences in blood pressure between patients with and without MS, while patients with MS needed a greater number of antihypertensive drugs than those without MS. Mean urinary salt and potassium excretions were 8.9+/-3.8 g/day and 1.9+/-0.7 g/day, respectively. Urinary salt excretion of <6 g (100 mmol of sodium)/day was achieved in 20% of the subjects. Urinary salt excretion in the patients with MS was significantly higher than that in the patients without (10.1+/-4.2 vs. 8.5+/-3.6 g/day; p<0.01). Only 16% of the patients with MS achieved salt restriction (<6 g/day). The patients with MS had a significantly greater the chance to eat out than the patients without MS. They were also less aware of the need to increase their vegetable consumption. The results suggested that MS is prevalent in Japanese hypertensive patients. Patients with MS showed higher urinary salt excretion and needed more antihypertensive drugs to manage their blood pressure. Dietary counseling focusing not only on sodium restriction but also on the need to increase fruit and vegetable consumption seems to be important.