The relationships between body mass index (BMI), fasting plasma glucose and insulin and blood pressure level have been investigated in a group of 2,144 healthy middle-aged men. The associations between BMI and blood pressure are largely independent of plasma glucose and insulin. Plasma glucose is strongly related to blood pressure in non-obese subjects. Plasma insulin is not associated with blood pressure independently of BMI and plasma glucose, although the simultaneous elevation of BMI, plasma glucose and insulin is strongly associated with blood pressure.