A 19-year-old male was admitted to our hospital for the treatment of severe hypertension with renal dysfunction. Two years before admission, his hypertension had been diagnosed as essential hypertension based on a series of examinations when his renal function was not impaired. Visits to his primary physician ended when he developed severe hypertension of 210/140 mmHg, at which time renal dysfunction and serum creatinine of 2.25 mg/dL were discovered. Renin and antidiuretic hormone were slightly elevated, but renal artery stenosis or other abnormalities were not detected by magnetic resonance imaging and computer tomography. After the hypertension was controlled by medication, a renal biopsy was performed to assess renal impairment. Histology demonstrated lesions compatible with thrombotic microangiopathy (TMA) and ischemic lesions, including fibrinoid necrosis, intimal thickening, occlusion in the small arteries, wrinkling and duplication of the glomerular basement membrane with microthrombi, and focal interstitial fibrosis. Renal function ameliorated after the hypertension was controlled. This case suggests that severe and accelerated hypertension can cause TMA with renal impairment even in young people.