Abstract The effect of a surgical cure of hypercortisolism on hypertension in 54 patients with Cushing's syndrome was assessed. The correlation between preoperative duration of hypertension and posttreatment blood pressure was significant ( P < .01). Restoration of normal cortisol was associated with blood pressure normalization in 39 out of 54 cases. Duration of hypertension of patients with normalized blood pressure was significantly shorter than that of patients with persistent hypertension post-operatively ( P < .0001). Duration of hypertension, ie, long-lasting exposure to increased cortisol, appears to be the determinant of persistent hypertension following successful surgery in Cushing's syndrome.