OBJECTIVE To study the relationships between blood pressure, insulin secretion and insulin resistance in obese female subjects. METHODS Evaluation of insulin-secretion and resistance respectively by blood C-peptide determination and glucose clamp technique in nonhypertensive and hypertensive obese female subjects. METHODS Outpatient clinic of University Hospital. METHODS 12 female obese subjects, six of whom were nonhypertensive, and six hypertensive; and nine nonobese nonhypertensive subjects as control. METHODS Baseline and during OGTT blood C-peptide as insulin secretion index; M, MCR and M/I ratio evaluated by euglycemic hyperinsulinemic clamp as expression of insulin resistance. RESULTS No difference is shown in C-peptide levels, between the two groups of obese subjects; the M, MCR and M/I values are significantly lower in hypertensive obese vs nonhypertensive obese subjects and controls (P < 0.001). Considering all the subjects, the same parameters are significantly inversely correlated with mean blood pressure values (P < 0.001). CONCLUSIONS In the groups of considered obese subjects, homogeneous for age, sex, body weight excess, fat distribution and glucose tolerance, blood pressure values are directly related to insulin resistance but not to insulin secretion.