Most often, low-renin hypertension in the child or adolescent has a clearly definable hormonal cause; thus while each of its numerous forms is moderately rare, a specific hormonal basis is to be expected. An endocrine evaluation is indicated after exclusion of cardiologic pathology or renovascular or portal abnormality in a hypertensive child. The evaluation should include analysis of catecholamine and of thyroid hormone plasma levels, and plasma renin activity (PRA) level. Hormonal hypertension with high or normal renin conditions is rare. Elevated blood pressure with high or normal renin levels may be in fact within normal range in the context of growth at upper percentile limits, possibly in conjunction with simple obesity. Diagnosis may be made at any age in most forms of low-renin hypertension.