Hypertensive encephalopathy rarely presents with predominant involvement of the brain stem and relative sparing of the supratentorial regions. We describe the MR imaging features in a patient with reversible brain stem hypertensive encephalopathy. Extensive hyperintensity was predominantly seen in brain stem regions on fluid-attenuated inversion-recovery and T2-weighted images. These lesions showed an increased apparent diffusion coefficient with the use of line scan diffusion-weighted imaging. The clinical findings and MR imaging abnormalities resolved with control of hypertension.