Seventeen alpha-hydroxylase deficiency (17OHD) syndrome is a rare genetic disorder of steroid biosynthesis causing decreased production of glucocorticoids and sex steroids and increased synthesis of mineralocorticoid precursors. There are only 130 cases reported worldwide with documented severe 17OHD. Here, we describe the clinical, hormonal, and molecular genetic characteristics of a Turkish patient with 17OHD, who presented to our clinic due to high blood pressure. A 29-year-old girl with 46,XY genotype was admitted to our nephrology clinic due to uncontrolled hypertension and hypokalemia. The diagnosis was suspected because of primary amenorrhea, absence of sexual maturation, hypertension, and hypokalemia. Endocrine investigation revealed low basal levels of all steroid hormones which require 17-hydroxylation for biosynthesis. Plasma concentrations of ACTH, FSH, and LH were elevated. Imaging did not reveal uterus or adnexial structures. The patient's hypertension and hypokalemia resolved after glucocorticoid replacement and treatment with potassium-sparing diuretics. 17OHD is a rare form of congenital adrenal hyperplasia in which defects in the biosynthesis of cortisol and sex steroids result in mineralocorticoid excess, hypokalemic hypertension, and sexual abnormalities such as pseudohermaphroditism in males, and sexual infantilism in females. 17OHD should be suspected in patients with hypokalemic hypertension and lack of secondary sexual development so that appropriate therapy can be implemented.