Thyroid hormones have several well-recognized effects on the vasculature and heart, resulting in characteristic cardiovascular changes in thyroid disease, including an increase in blood pressure. In hyperthyroidism reduced systemic vascular resistance and increased blood volume lead to an enhanced preload, which, in association with reduced afterload, improved contractility, as well as increased beta-adrenergic activity, results in isolated systolic hypertension based on enhanced stroke volume and cardiac output. In contrast, hypothyroidism causes increased systemic vascular resistance in association with decreased arterial compliance resulting in elevated diastolic blood pressure. Therefore in the evaluation of arterial hypertension secondary hypertension based on thyroid disease should always be considered, especially given the fact that blood pressure changes in the course of thyroid dysfunction are usually reversible upon adequate treatment of hypo- or hyperthyroidism.